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Revision History for A324847 (Underlined text is an addition; strikethrough text is a deletion.)

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A324847 Numbers divisible by at least one of their prime indices.
(history; published version)
#10 by Alois P. Heinz at Tue Mar 19 17:38:47 EDT 2019
STATUS

proposed

approved

#9 by Robert Israel at Tue Mar 19 15:02:54 EDT 2019
STATUS

editing

proposed

#8 by Robert Israel at Tue Mar 19 15:02:44 EDT 2019
COMMENTS

If n is in the sequence, then so are all multiples of n. - Robert Israel, Mar 19 2019

LINKS

Robert Israel, <a href="/A324847/b324847.txt">Table of n, a(n) for n = 1..10000</a>

MAPLE

filter:= proc(n) local F;

F:= map(numtheory:-pi, numtheory:-factorset(n));

ormap(t -> n mod t = 0, F);

end proc:

select(filter, [$1..200]); # Robert Israel, Mar 19 2019

STATUS

proposed

editing

#7 by Michel Marcus at Tue Mar 19 14:29:43 EDT 2019
STATUS

editing

proposed

#6 by Michel Marcus at Tue Mar 19 14:21:47 EDT 2019
PROG

(PARI) isok(n) = {my(f = factor(n)[, 1]); for (k=1, #f, if (!(n % primepi(f[k])), return (1)); ); return (0); } \\ Michel Marcus, Mar 19 2019

STATUS

approved

editing

#5 by Susanna Cuyler at Tue Mar 19 07:15:40 EDT 2019
STATUS

proposed

approved

#4 by Gus Wiseman at Mon Mar 18 22:30:31 EDT 2019
STATUS

editing

proposed

#3 by Gus Wiseman at Mon Mar 18 22:30:21 EDT 2019
CROSSREFS

Cf. A324695, A324741, A324743, A324847, A324756, A324758, A324765, A324848, A324849, A324850, A324852, A324853.

Cf. A324848, A324849, A324850, A324852, A324853.

#2 by Gus Wiseman at Mon Mar 18 11:33:04 EDT 2019
NAME

allocatedNumbers divisible by at least one of fortheir Gusprime Wisemanindices.

DATA

2, 4, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 45, 46, 48, 50, 52, 54, 55, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 75, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 105, 106, 108, 110, 112, 114, 116

OFFSET

1,1

COMMENTS

A prime index of n is a number m such that prime(m) divides n.

EXAMPLE

The sequence of terms together with their prime indices begins:

2: {1}

4: {1,1}

6: {1,2}

8: {1,1,1}

10: {1,3}

12: {1,1,2}

14: {1,4}

15: {2,3}

16: {1,1,1,1}

18: {1,2,2}

20: {1,1,3}

22: {1,5}

24: {1,1,1,2}

26: {1,6}

28: {1,1,4}

30: {1,2,3}

32: {1,1,1,1,1}

34: {1,7}

36: {1,1,2,2}

MATHEMATICA

Select[Range[100], Or@@Cases[If[#==1, {}, FactorInteger[#]], {p_, _}:>Divisible[#, PrimePi[p]]]&]

CROSSREFS

Complement of A324846.

Cf. A003963, A056239, A112798, A120383, A289509, A290822, A304360, A306844.

Cf. A324695, A324741, A324743, A324847, A324756, A324758, A324765.

Cf. A324848, A324849, A324850, A324852, A324853.

KEYWORD

allocated

nonn

AUTHOR

Gus Wiseman, Mar 18 2019

STATUS

approved

editing

#1 by Gus Wiseman at Sun Mar 17 08:05:05 EDT 2019
NAME

allocated for Gus Wiseman

KEYWORD

allocated

STATUS

approved

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Last modified August 29 06:09 EDT 2024. Contains 375510 sequences. (Running on oeis4.)