A364550 Numbers k such that k is a multiple of A005941(k).

1, 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 24, 32, 40, 48, 64, 80, 96, 128, 160, 192, 256, 320, 384, 512, 640, 768, 1024, 1280, 1536, 2048, 2560, 3072, 3125, 4096, 5120, 6144, 6250, 7875, 8192, 10240, 12005, 12288, 12500, 13365, 15750, 16384, 20480, 22869, 23595, 24010, 24576, 25000, 26730, 31500, 32768, 40960, 45738, 46475

Offset

1,2

Comments

Numbers k such that k is a multiple of 1+A156552(k).

If k is a term, then also 2*k is present in this sequence, and vice versa.

Links

Table of n, a(n) for n=1..59.

Prog

(PARI) A005941(n) = { my(f=factor(n), p, p2=1, res=0); for(i=1, #f~, p = 1 << (primepi(f[i, 1])-1); res += (p * p2 * (2^(f[i, 2])-1)); p2 <<= f[i, 2]); (1+res) }; \\ (After David A. Corneth's program for A156552) - Antti Karttunen, Jul 28 2023
isA364550(n) = !(n%A005941(n));

Crossrefs

Cf. A005941, A156552, A364548.

Subsequence of A364560.

Subsequences: A029747, A364551 (odd terms).

Cf. also

Sequence in context: A364544 A253789 A364546 * A029747 A095381 A233205

Adjacent sequences: A364547 A364548 A364549 * A364551 A364552 A364553

Keyword

nonn

Author

Antti Karttunen, Jul 28 2023

Status

approved