A085743 a(n) = T(n^3) - T(n^2), where T() are the triangular numbers (A000217).

0, 0, 26, 333, 1944, 7550, 22770, 57771, 129248, 262764, 495450, 879065, 1483416, 2400138, 3746834, 5671575, 8357760, 12029336, 16956378, 23461029, 31923800, 42790230, 56577906, 73883843, 95392224, 121882500, 154237850, 193454001

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Formula

a(n) = (n-1)*n^2*(n^3 + n^2 + 1)/2.

Example

a(3) = T(3^3) - T(3^2) = T(27) - T(9) = 378 - 45 = 333.

Prog

(PARI) t(n)=n*(n+1)/2; for(n=0, 50, print1(t(n^3)-t(n^2)", "))
(Magma) [(n-1)*n^2*(n^3+n^2+1)/2: n in [0..40]]; // Vincenzo Librandi, Sep 14 2011

Crossrefs

Cf. A000217.

Sequence in context: A202292 A010942 A022621 * A205494 A125438 A126919

Adjacent sequences: A085740 A085741 A085742 * A085744 A085745 A085746

Keyword

nonn,easy

Author

Jon Perry, Jul 21 2003

Status

approved