A100256 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A100256

Squares of second pentagonal numbers: a(n) = (1/4)*n^2*(3*n+1)^2.

1

0, 4, 49, 225, 676, 1600, 3249, 5929, 10000, 15876, 24025, 34969, 49284, 67600, 90601, 119025, 153664, 195364, 245025, 303601, 372100, 451584, 543169, 648025, 767376, 902500, 1054729, 1225449, 1416100, 1628176, 1863225, 2122849

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..31.

Leonhard Euler, De mirabilibus proprietatibus numerorum pentagonalium, par. 29

Leonhard Euler, On the remarkable properties of the pentagonal numbers, arXiv:math/0505373 [math.HO], 2006.

FORMULA

G.f.: x*(4+29*x+20*x^2+x^3)/(1-x)^5. - Colin Barker, Feb 14 2012

CROSSREFS

Equals A005449(n)^2. Cf. A100255.

Sequence in context: A166826 A295535 A078187 * A163944 A000596 A113525

Adjacent sequences: A100253 A100254 A100255 * A100257 A100258 A100259

KEYWORD

nonn,easy

AUTHOR

Ralf Stephan, Nov 13 2004

STATUS

approved