login
A373974
a(n) is the number of divisors of n that can be expressed as a sum of 2 distinct positive cubes.
4
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
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
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 24 2024
STATUS
approved