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a(n) = A145909(n)/8.
3

%I #19 Mar 12 2022 10:28:49

%S 0,1,1,2,10,5,7,28,4,5,55,22,26,91,35,40,136,17,19,190,70,77,253,92,

%T 100,325,39,42,406,145,155,496,176,187,595,70,74,703,247,260,820,287,

%U 301,946,110,115,1081,376,392,1225,425,442,1378

%N a(n) = A145909(n)/8.

%H G. C. Greubel, <a href="/A145911/b145911.txt">Table of n, a(n) for n = 0..5000</a>

%H <a href="/index/Rec#order_27">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,-3,0,0,0,0,0,0,0,0,1).

%F a(n) = A106619(n)*A106619(n+1).

%p A061039:= proc(n) numer(1/9-1/n^2) ; end proc:

%p A145909:= proc(n) ; A061039(6*n+3); end proc:

%p A145911:= proc(n) ; A145909(n)/8; end proc:

%p seq(A145911(n),n=0..80) ; # _R. J. Mathar_, Jan 06 2011

%t Numerator[(1/9)*(1 -1/(2*Range[0, 75] +1)^2)]/8 (* _G. C. Greubel_, Mar 12 2022 *)

%o (Sage) [numerator((1/9)*(1 - 1/(2*n+1)^2))/8 for n in (0..75)] # _G. C. Greubel_, Mar 12 2022

%Y Cf. A061039, A106619, A145909.

%K nonn,easy

%O 0,4

%A _Paul Curtz_, Oct 24 2008