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Squares of even tetrahedral numbers (A015220).
2

%I #24 Mar 07 2022 13:03:25

%S 0,16,100,400,3136,7056,14400,48400,81796,132496,313600,462400,665856,

%T 1299600,1768900,2371600,4096576,5290000,6760000,10732176,13351716,

%U 16483600,24601600,29767936,35808256,50979600,60372900,71166096,97614400,113635600,131790400,175403536

%N Squares of even tetrahedral numbers (A015220).

%H <a href="/index/Rec#order_19">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,6,-6,0,-15,15,0,20,-20,0,-15,15,0,6,-6,0,-1,1).

%F From _Amiram Eldar_, Mar 07 2022: (Start)

%F a(n) = A015220(n)^2.

%F Sum_{n>=1} 1/a(n) = 27*(Pi^2 + Pi - 13)/4. (End)

%t Select[Binomial[Range[0,40]+2,3],EvenQ]^2 (* _Harvey P. Dale_, Jan 19 2012 *)

%Y Cf. A000292, A015220, A014795.

%K nonn,easy

%O 0,2

%A _Mohammad K. Azarian_

%E More terms from _Erich Friedman_

%E a(0) and more terms from _Amiram Eldar_, Mar 07 2022