A154617 Eleven times hexagonal numbers: a(n) = 11*n*(2*n-1).

0, 11, 66, 165, 308, 495, 726, 1001, 1320, 1683, 2090, 2541, 3036, 3575, 4158, 4785, 5456, 6171, 6930, 7733, 8580, 9471, 10406, 11385, 12408, 13475, 14586, 15741, 16940, 18183, 19470, 20801, 22176, 23595, 25058, 26565, 28116, 29711, 31350, 33033, 34760, 36531, 38346

Offset: 0

Author

Omar E. Pol, Jan 13 2009

Keywords

• easy
• nonn

Comments

Sequence found by reading the line from 0, in the direction 0, 11, ..., in the square spiral whose vertices are the generalized tridecagonal numbers A195313. - Omar E. Pol, Sep 18 2011

Links

• Ivan Panchenko, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Crossrefs

Cf. A000384, A002939, A094159, A152745, A153781, A195313.

Programs

PARI

a(n)=11*n*(2*n-1) \\ Charles R Greathouse IV, Jun 17 2017

Formula

a(n) = 22*n^2 - 11*n = 11*A000384(n).

a(n) = a(n-1) + 44*n - 33 (with a(0)=0). - Vincenzo Librandi, Dec 15 2010

From Elmo R. Oliveira, Dec 15 2024: (Start)

G.f.: 11*x*(1 + 3*x)/(1 - x)^3.

E.g.f.: 11*x*(1 + 2*x)*exp(x).

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n >= 3. (End)