1,1

The numbers c in A225909.

The sequence is infinite, because A226903 is a parametrized infinite subsequence.

Chai Wah Wu, Table of n, a(n) for n = 1..5000

a(n) = (-3 + sqrt(9 + 12*(A225909(n) - 1)))/6

(5+1)^3 - 5^3 = 3^3 + 4^3, so 5 is a member.

Cf. A225909, A226903.

Sequence in context: A219049 A245534 A302393 * A026595 A037233 A197539

Adjacent sequences: A226899 A226900 A226901 * A226903 A226904 A226905

nonn

Jonathan Sondow, Jun 21 2013

approved