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

%I #6 Apr 30 2014 01:27:34

%S 0,4,49,225,676,1600,3249,5929,10000,15876,24025,34969,49284,67600,

%T 90601,119025,153664,195364,245025,303601,372100,451584,543169,648025,

%U 767376,902500,1054729,1225449,1416100,1628176,1863225,2122849

%N Squares of second pentagonal numbers: (1/4) n^2(3n+1)^2.

%H L. Euler, <a href="http://math.dartmouth.edu/~euler/pages/E542.html">De mirabilibus proprietatibus numerorum pentagonalium</a>, par. 29

%H L. Euler, <a href="http://arXiv.org/abs/math.HO/0505373">On the remarkable properties of the pentagonal numbers</a>

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

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

%K nonn

%O 0,2

%A _Ralf Stephan_, Nov 13 2004