A181763 - OEIS

%I #19 Aug 14 2022 03:02:30

%S 0,25,9,441,4,2025,225,5929,36,13689,1225,27225,144,48841,3969,81225,

%T 400,127449,9801,190969,900,275625,20449,385641,1764,525625,38025,

%U 700569,3136,915849,65025,1177225,5184,1490841,104329,1863225,8100

%N a(n) = A061037(n)^2.

%C A061038(n)/a(n+2) for n >= 2 gives the reduced fractions 1/9, 4/49, 4, 4/81, 1/25, 4/121, 16/9, 4/169, ...

%H G. C. Greubel, <a href="/A181763/b181763.txt">Table of n, a(n) for n = 2..1000</a>

%F Sum_{n>=3} 1/a(n) = 79*Pi^2/192 - 65/18. - _Amiram Eldar_, Aug 14 2022

%t A061037[n_] := Numerator[(n - 2)*(n + 2)/(4 n^2)]; Table[A061037[n]^2, {n, 2, 100}] (* _G. C. Greubel_, Sep 19 2018 *)

%o (Magma) A061037:=func< n | Numerator(1/4-1/n^2) >; A181763:=func< n | A061037(n)^2 >; [ A181763(n): n in [2..50] ]; // _Klaus Brockhaus_, Jan 09 201

%o (PARI) a(n) = numerator((n-2)*(n+2)/(4*n^2));

%o for(n=2,100, print1(a(n)^2, ", ")) \\ _G. C. Greubel_, Sep 19 2018

%Y Cf. A061037, A061038.

%K nonn

%O 2,2

%A _Paul Curtz_, Nov 14 2010