A277045 - OEIS

A277045

Irregular triangle T(n,k) read by rows giving the number of partitions of length k such that all of the members of the partition are distinct and in A003586.

1, 1, 1, 1, 1, 1, 0, 2, 1, 1, 1, 0, 2, 1, 1, 1, 1, 1, 2, 2, 0, 3, 1, 1, 0, 2, 3, 1, 2, 3, 1, 0, 2, 4, 1, 0, 2, 3, 2, 0, 2, 4, 3, 1, 1, 4, 2, 1, 0, 2, 4, 3, 1, 2, 4, 4, 1, 0, 2, 5, 4, 1, 0, 3, 3, 5, 1, 0, 2, 6, 5, 2, 0, 2, 5, 5, 3, 0, 0, 7, 5, 3, 1, 2, 4, 7, 3, 1, 0, 2, 5, 8, 2, 1, 0, 2, 5, 6, 5, 1

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OFFSET

1,8

COMMENTS

If n is in A003586, then T(n,1) = 1, else T(n,1) = 0.

T(n,k) also is the number of ways of representing n involving k 1's in the base(2,3) or "dual-base number system" (i.e., base(2,3)).

The number of "canonic" representations of n in a dual-base number system as defined by the reference as having the lowest number of terms, appears in the first column of the triangle with a value greater than 0.

A237442(n) = the least k with a nonzero value.

REFERENCES

V. Dimitrov, G. Jullien, R. Muscedere, Multiple Number Base System Theory and Applications, 2nd ed., CRC Press, 2012, pp. 35-39.

LINKS

Table of n, a(n) for n=1..100.

EXAMPLE

Triangle starts:

1,1

0,2

1,1,1

0,2,1

1,1,1

1,2,2

0,3,1,1

0,2,3

1,2,3,1

0,2,4,1

0,2,3,2

0,2,4,3

1,1,4,2,1

0,2,4,3

1,2,4,4,1

0,2,5,4,1

0,3,3,5,1

...

Row n = 10 has terms {0,3,1,1} because 10 is not in A003586 thus k = 1 has value 0. The partitions of 10 that have distinct members that are in A003586 are {{1,9},{2,8},{4,6},{1,3,6},{1,2,3,4}}, thus there are 3 partitions of length k = 2, 1 of length k = 3, and 1 with k = 4. A237442(10) = 2.

MATHEMATICA

nn = 6^6; t = Sort@ Select[Flatten@ KroneckerProduct[2^Range[0, Ceiling@ Log2@ nn], 3^Range[0, Ceiling@ Log[3, nn]]], # <= nn &]; Table[BinCounts[#, {1, Max@ # + 1, 1}] &@ Map[Length, #] &@ Select[Subsets@ TakeWhile[t, # <= n &], Total@ # == n &], {n, 40}]

CROSSREFS

Cf. A003586, A237442, A276380.

Sequence in context: A287364 A340676 A117162 * A146061 A331186 A375847

Adjacent sequences: A277042 A277043 A277044 * A277046 A277047 A277048

KEYWORD

nonn,tabf

AUTHOR

Michael De Vlieger, Sep 27 2016

STATUS

approved