A217728 a(n) = a(n-1)^3 + a(n-2)^3 - (a(n-1) - a(n-2))^3, a(1) = a(2) = 1.

1, 1, 2, 8, 304, 2160640, 4256950094225408, 117462917657284681348398871061442068480

Offset

1,3

Comments

a(9) has 93 digits and thus is too long to be added. - Giovanni Resta, Mar 22 2013

Links

Table of n, a(n) for n=1..8.

Example

a(3) = (1)^3 + (1)^3 - (1-1)^3 = 2.
a(4) = (2)^3 + (1)^3 - (2 - 1)^3 = 8.
a(5) = (8)^3 + (2)^3 - (8 - 2)^3 = 512 + 8 - 216 = 304.

Crossrefs

Sequence in context: A013027 A012918 A012913 * A013086 A012536 A012541

Adjacent sequences: A217725 A217726 A217727 * A217729 A217730 A217731

Keyword

nonn

Author

Gregory Gabovich, Mar 21 2013

Extensions

a(8) from Giovanni Resta, Mar 22 2013

Status

approved