login
A307609
Number of partitions of n^3 into consecutive positive cubes.
2
1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
OFFSET
1,6
FORMULA
a(n) = [x^(n^3)] Sum_{i>=1} Sum_{j>=i} Product_{k=i..j} x^(k^3).
a(n) = A297199(A000578(n)).
a(n) >= 2 for n in A097811.
EXAMPLE
20^3 = 11^3 + 12^3 + 13^3 + 14^3, so a(20) = 2.
2856^3 = 213^3 +...+ 555^3 = 273^3 +...+ 560^3, so a(2856) = 3. See also Donovan Johnson's comment in A097811. - Antti Karttunen, Aug 22 2019
PROG
(PARI)
A297199(n) = { my(s=0, k=1, c); while((c=k^3) <= n, my(u=n-c, i=k); while(u>0, i++; c = i^3; u=u-c); s += (!u); k++); (s); };
A307609(n) = A297199(n^3); \\ Antti Karttunen, Aug 22 2019
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Apr 18 2019
STATUS
approved