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Revision History for A317658 (Underlined text is an addition; strikethrough text is a deletion.)

Showing entries 1-10 | older changes
A317658 Number of positions in the n-th free pure symmetric multifunction (with empty expressions allowed) with one atom.
(history; published version)
#11 by Alois P. Heinz at Tue Sep 11 21:15:38 EDT 2018
STATUS

proposed

approved

#10 by Gus Wiseman at Tue Sep 11 18:22:51 EDT 2018
STATUS

editing

proposed

#9 by Gus Wiseman at Tue Sep 11 18:22:06 EDT 2018
COMMENTS

Also the number of positions in the orderless Mathematica expression with e-number n.

EXAMPLE

The first twenty free pure symmetric multifunction (with emptyMathematica expressions allowed)::

Discussion
Tue Sep 11 18:22
Gus Wiseman: Removed "Mathematica" from the name.
#8 by Gus Wiseman at Tue Sep 11 01:51:05 EDT 2018
NAME

Number of positions in the n-th free pure symmetric orderlessmultifunction (with Mathematicaempty expressions allowed) with one atom.

COMMENTS

The definition ofGiven orderlessa Mathematicapositive expressioninteger isn > 1 similarwe toconstruct thata ofunique free pure symmetric multifunction (see A280000e(n) exceptby expressing n as a power of a number that is not a perfect power to a product of emptyprime expressionsnumbers: n = rad(x)^(prime(y_1) * ... * prime(y_k)) where f[] arerad = A007916. Then allowed.e(n) = e(x)[e(y_1), ..., e(y_k)].

Given a positive integer n > 1 we construct a unique orderless Mathematica expression e(n) by expressing n as a power of a number that is not a perfect power to a product of prime numbers: n = rad(x)^(prime(y_1) * ... * prime(y_k)) where rad = A007916. Then e(n) = e(x)[e(y_1), ..., e(y_k)].

EXAMPLE

The first twenty free pure symmetric orderlessmultifunction (with Mathematicaempty expressions: allowed):

STATUS

approved

editing

#7 by Susanna Cuyler at Fri Aug 03 08:17:20 EDT 2018
STATUS

proposed

approved

#6 by Gus Wiseman at Fri Aug 03 06:02:47 EDT 2018
STATUS

editing

proposed

#5 by Gus Wiseman at Fri Aug 03 06:01:46 EDT 2018
FORMULA

e(2^prime(2^prime(2^^n) = ^...))) = o[o[...o[xo]]].

e(primerad(prime(...primerad(1)))) = rad(...)^2)^2)^2) = o[o][o]...[o].

#4 by Gus Wiseman at Fri Aug 03 05:42:45 EDT 2018
COMMENTS

Given a positive integer n > 1 we construct a unique orderless Mathematica expression e(n) by expressing n as a power of a number that is not a perfect power to a product of prime numbers : n = rad(x)^(prime(y_1) * ... * prime(y_k)) where rad = A007916. Then e(n) = e(x)[e(y_1), ..., e(y_k)].

#3 by Gus Wiseman at Fri Aug 03 04:56:14 EDT 2018
CROSSREFS

Cf. A001003, A052893, A053492, A255906, A277996, A279944, A280000, A317652, A317653, A317654, A317655, A317656.

Cf. A317652, A317653, A317654, A317655, A317656.

#2 by Gus Wiseman at Fri Aug 03 04:49:25 EDT 2018
NAME

allocatedNumber of positions in the n-th orderless Mathematica expressions forwith Gusone Wisemanatom.

DATA

1, 2, 3, 3, 4, 4, 5, 4, 4, 5, 6, 5, 5, 6, 7, 4, 6, 6, 7, 8, 5, 7, 7, 8, 5, 9, 5, 6, 8, 8, 9, 5, 6, 10, 6, 5, 7, 9, 9, 10, 6, 7, 11, 7, 6, 8, 10, 10, 6, 11, 7, 8, 12, 8, 7, 9, 11, 11, 7, 12, 8, 9, 13, 5, 9, 8, 10, 12, 12, 8, 13, 9, 10, 14, 6, 10, 9, 11, 13, 13

OFFSET

1,2

COMMENTS

The definition of orderless Mathematica expression is similar to that of free pure symmetric multifunction (see A280000) except that empty expressions f[] are allowed.

Given a positive integer n > 1 we construct a unique orderless Mathematica expression e(n) by expressing n as a power of a number that is not a perfect power to a product of prime numbers n = rad(x)^(prime(y_1) * ... * prime(y_k)) where rad = A007916. Then e(n) = e(x)[e(y_1), ..., e(y_k)].

LINKS

Mathematica Reference, <a href="http://reference.wolfram.com/mathematica/ref/Orderless.html">Orderless</a>

FORMULA

a(rad(x)^(prime(y_1) * ... * prime(y_k)) = a(x) + a(y_1) + ... + a(y_k).

e(2^(2^n)) = o[o,...,o].

e(2^^n) = o[o[...o[x]]].

e(prime(prime(...prime(1)))) = o[o][o]...[o].

EXAMPLE

The first twenty orderless Mathematica expressions:

1: o

2: o[]

3: o[][]

4: o[o]

5: o[][][]

6: o[o][]

7: o[][][][]

8: o[o[]]

9: o[][o]

10: o[o][][]

11: o[][][][][]

12: o[o[]][]

13: o[][o][]

14: o[o][][][]

15: o[][][][][][]

16: o[o,o]

17: o[o[]][][]

18: o[][o][][]

19: o[o][][][][]

20: o[][][][][][][]

MATHEMATICA

nn=100;

radQ[n_]:=If[n===1, False, GCD@@FactorInteger[n][[All, 2]]===1];

rad[n_]:=rad[n]=If[n===0, 1, NestWhile[#+1&, rad[n-1]+1, Not[radQ[#]]&]];

Clear[radPi]; Set@@@Array[radPi[rad[#]]==#&, nn];

exp[n_]:=If[n===1, x, With[{g=GCD@@FactorInteger[n][[All, 2]]}, Apply[exp[radPi[Power[n, 1/g]]], exp/@Flatten[Cases[FactorInteger[g], {p_?PrimeQ, k_}:>ConstantArray[PrimePi[p], k]]]]]];

Table[exp[n], {n, 1, nn}]

CROSSREFS

First differs from A277615 at a(128) = 5, A277615(128) = 6.

Cf. A001003, A052893, A053492, A255906, A277996, A279944, A280000, A317652, A317653, A317654, A317655, A317656.

KEYWORD

allocated

nonn

AUTHOR

Gus Wiseman, Aug 03 2018

STATUS

approved

editing

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