A364964 Numbers k such that k is a multiple of A243071(k).

2, 3, 4, 6, 8, 12, 16, 24, 27, 32, 48, 54, 64, 96, 108, 128, 192, 216, 256, 315, 384, 432, 512, 630, 768, 864, 1024, 1260, 1536, 1728, 2048, 2520, 3003, 3072, 3456, 4096, 5040, 6006, 6144, 6912, 8192, 10080, 12012, 12288, 13824, 16384, 20160, 24024, 24576, 27648, 32768, 40320, 42757, 48048, 49152, 55296, 65536

Offset: 1

Author

Antti Karttunen, Sep 01 2023

Keywords

• nonn

Comments

For k > 1, if k is a term, then also 2*k is present in this sequence, and vice versa.

Crossrefs

Sequence A163511(A364494(n)), for n>=0, sorted into ascending order.

Cf. A007283 (subsequence), A364965 (odd terms).

Cf. also A364497, A364550.

Programs

PARI

A243071(n) = if(n<=2, n-1, 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]); ((3<<#binary(res\2))-res-1)); \\ (Combining programs given in A156552 and A054429)
isA364964(n) = ((n>1)&&!(n%A243071(n)));