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A364550
Numbers k such that k is a multiple of A005941(k).
4
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.
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
Subsequence of A364560.
Subsequences: A029747, A364551 (odd terms).
Cf. also
Sequence in context: A364544 A253789 A364546 * A029747 A095381 A233205
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 28 2023
STATUS
approved