A269842 Integers n such that A000330(n) is the sum of 2 positive cubes.

6, 669, 2456, 5642, 8255, 15855, 50704, 63752, 82621, 112384, 1151884, 1191025, 1203999, 1228825, 1244256, 1459371, 1661343, 1819141, 2264191, 2445632, 2451193, 2812562, 2875250, 3425382, 3792000, 4866303, 5123958, 5587967

Offset

1,1

Comments

Corresponding square pyramidal numbers are 91, 100029995, 4941161316, 59881606785, 187546467680, 1328674410280, ...

Links

Table of n, a(n) for n=1..28.

Example

6 is a term because A000330(6) = 91 = 3^3 + 4^3.

Prog

(PARI) isA003325(n) = for(k=1, sqrtnint(n\2, 3), ispower(n-k^3, 3) && return(1));
for(n=0, 1e7, if(isA003325(n*(n+1)*(2*n+1)/6), print1(n, ", ")));

Crossrefs

Cf. A000330, A003325.

Sequence in context: A222743 A222720 A309597 * A333639 A331724 A046985

Adjacent sequences: A269839 A269840 A269841 * A269843 A269844 A269845

Keyword

nonn

Author

Altug Alkan, Mar 06 2016

Extensions

a(11)-a(28) from Chai Wah Wu, Mar 08 2016

Status

approved