A085742 a(n) = T(n^3) - T(n), where T() are the triangular numbers (A000217).

0, 0, 33, 372, 2070, 7860, 23415, 58968, 131292, 266040, 500445, 886380, 1493778, 2414412, 3766035, 5696880, 8390520, 12071088, 17008857, 23526180, 32003790, 42887460, 56695023, 74023752, 95558100, 122077800, 154466325, 193719708

Offset

0,3

Links

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

Formula

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

Example

a(3) = T(3^3) - T(3) = T(27) - T(3) = 378 - 6 = 372.

Prog

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

Crossrefs

Cf. A000217.

Sequence in context: A209359 A264282 A167963 * A244502 A202256 A324950

Adjacent sequences: A085739 A085740 A085741 * A085743 A085744 A085745

Keyword

nonn,easy

Author

Jon Perry, Jul 21 2003

Status

approved