This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A060493 #30 Apr 02 2025 15:57:33
%S A060493 0,1,21,147,627,2002,5278,12138,25194,48279,86779,148005,241605,
%T A060493 380016,578956,857956,1240932,1756797,2440113,3331783,4479783,5939934,
%U A060493 7776714,10064110,12886510,16339635,20531511,25583481,31631257,38826012,47335512,57345288,69059848
%N A060493 A diagonal of A036969.
%H A060493 Seiichi Manyama, <a href="/A060493/b060493.txt">Table of n, a(n) for n = 0..10000</a>
%H A060493 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-7,1).
%F A060493 From _Benoit Cloitre_, Mar 20 2004: (Start)
%F A060493 a(n) = n*(n + 1)*(n + 2)*(2*n + 1)*(2*n + 3)*(5*n - 1)/360.
%F A060493 a(n) = Sum_{k=1..n} k^2 * Sum_{i=1..k} i^2.
%F A060493 a(n) = Sum_{k=1..n} k^2*A000330(k). (End)
%F A060493 G.f.: -x*(4*x^3+21*x^2+14*x+1) / (x-1)^7. - _Colin Barker_, Dec 19 2012
%F A060493 a(n) = 2/(2*n)! * Sum_{j = 1..n} (-1)^(n+j) * j^(2*n+4) * binomial(2*n, n-j). - _Peter Bala_, Mar 31 2025
%o A060493 (PARI) a(n)=n*(n + 1)*(n + 2)*(2*n + 1)*(2*n + 3)*(5*n - 1)/360
%Y A060493 Cf. A000330, A036969, A351105.
%K A060493 nonn,easy
%O A060493 0,3
%A A060493 Larry Reeves (larryr(AT)acm.org), Mar 20 2001
%E A060493 Missing a(0)=0 inserted by _Alois P. Heinz_, Feb 19 2022