A364965 Odd numbers k such that k is a multiple of A243071(k).

3, 27, 315, 3003, 42757, 72765, 195195, 799425, 13873275, 18131225

Offset: 1

Author

Antti Karttunen, Sep 01 2023

Keywords

• nonn
• more

Crossrefs

Odd terms in A364964.

Sequence A163511(A364495(n)), for n>1, sorted into ascending order.

Cf. A243071.

Cf. also A364498, A364551.

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)
isA364965(n) = ((n>1)&&(n%2)&&!(n%A243071(n)));