A373974 a(n) is the number of divisors of n that can be expressed as a sum of 2 distinct positive cubes.

0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2

Offset

1,72

Comments

Number of terms of A024670 that divide n.

Links

Antti Karttunen, Table of n, a(n) for n = 1..100080

Formula

a(n) = Sum_{d|n} A373971(d).

a(n) >= A373973(n).

Prog

(PARI)
A373971(n) = if(0==n, n, for(i=ceil(sqrtn(n\2+1, 3)), sqrtn(n-(1/2), 3), if(ispower(n-(i^3), 3), return(1))); 0); \\ After M. F. Hasler's Apr 12 2008 program in A024670.
A373974(n) = sumdiv(n, d, A373971(d));

Crossrefs

Cf. A024670, A359225 (indices of terms > 0), A373973.

Inverse Möbius transform of A373971.

Sequence in context: A355549 A347438 A374017 * A245196 A259362 A303553

Adjacent sequences: A373971 A373972 A373973 * A373975 A373976 A373977

Keyword

nonn

Author

Antti Karttunen, Jun 24 2024

Status

approved