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 A134153 #15 Sep 24 2024 06:17:10
%S A134153 1,25,79,163,277,421,595,799,1033,1297,1591,1915,2269,2653,3067,3511,
%T A134153 3985,4489,5023,5587,6181,6805,7459,8143,8857,9601,10375,11179,12013,
%U A134153 12877,13771,14695,15649,16633,17647,18691,19765,20869,22003,23167
%N A134153 a(n) = 15*n^2 + 9*n + 1.
%C A134153 A119617 is union of A134153 and A134154. A000538(n) is divisible by A000330(n) if and only n is congruent to {1, 3} mod 5 (see A047219). A134154(n) is case when n is congruent to 1 mod 5 see cases 2)
%H A134153 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A134153 a(n) = 15*n^2 + 9*n + 1.
%F A134153 a(n) = (3*(5*n + 1)^2 + 3*(5*n + 1) - 1)/5.
%F A134153 a(n) = (Sum_{k=1..5*n+1} k^4) / (Sum_{k=1..5*n+1} k^2).
%F A134153 G.f.: -(1+22*x+7*x^2)/(-1+x)^3. - _R. J. Mathar_, Nov 14 2007
%t A134153 Table[1 + 9 n + 15 n^2, {n, 0, 50}]
%t A134153 Table[Sum[k^4, {k, 1, 5m + 1}]/Sum[k^2, {k, 1, 5m + 1}], {m, 0, 10}]
%o A134153 (PARI) a(n)=15*n^2+9*n+1 \\ _Charles R Greathouse IV_, Jun 17 2017
%Y A134153 Cf. A119617, A134154.
%K A134153 nonn,easy
%O A134153 0,2
%A A134153 _Artur Jasinski_, Oct 10 2007
%E A134153 Offset corrected and some punctuation added by _R. J. Mathar_, Jul 09 2009