A192736 Right edge of the triangle in A033291.

1, 4, 12, 28, 50, 84, 133, 192, 270, 370, 484, 624, 793, 980, 1200, 1456, 1734, 2052, 2413, 2800, 3234, 3718, 4232, 4800, 5425, 6084, 6804, 7588, 8410, 9300, 10261, 11264, 12342, 13498, 14700, 15984, 17353, 18772, 20280, 21880, 23534, 25284, 27133, 29040

Offset

1,2

Comments

a(n) = A007980(n-1) * n.

Links

Table of n, a(n) for n=1..44.

Index entries for linear recurrences with constant coefficients, signature (2,-1,2,-4,2,-1,2,-1).

Formula

G.f.: x*(2*x^5+2*x^4+6*x^3+5*x^2+2*x+1) / ((x-1)^4*(x^2+x+1)^2). - Colin Barker, Mar 31 2013

a(n) = n^3/3 + n^2/3 + O(n). - Charles R Greathouse IV, May 28 2026

Prog

(Haskell) See A033291.
(PARI) a(n)=(n^3+n^2+[0, 1, 0][n%3+1]*n)/3 \\ Charles R Greathouse IV, May 28 2026

Crossrefs

Cf. A192735, A033291, A007980.

Sequence in context: A178571 A278211 A342235 * A109629 A112087 A166019

Adjacent sequences: A192733 A192734 A192735 * A192737 A192738 A192739

Keyword

nonn,easy,changed

Author

Reinhard Zumkeller, Jul 08 2011

Status

approved