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 A144941 #23 Sep 08 2022 08:45:38
%S A144941 1,36,753,41348,868769,47715364,1002558481,55063488516,1156951618113,
%T A144941 63543218031908,1335121164743729,73328818545333124,
%U A144941 1540728667162644961,84621393058096392996,1777999546784527541073,97653014260224692184068
%N A144941 Numbers k such that 6*k-1 = A144796(k).
%C A144941 Also the index of a pentagonal number which is equal to the sum of two consecutive pentagonal numbers. - _Colin Barker_, Dec 22 2014
%H A144941 Colin Barker, <a href="/A144941/b144941.txt">Table of n, a(n) for n = 1..653</a>
%H A144941 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,1154,-1154,-1,1).
%F A144941 For the odd and even indices respectively the same recurrence is obtained: a(n+2) = 1154*a(n+1) - a(n) - 192.
%F A144941 We also have a(n+2) = 577*a(n+1) - 96 + 68*sqrt((72*a(n)^2-24*a(n)-32)).
%F A144941 G.f.: x*(1 + 35*x - 437*x^2 + 205*x^3 + 4*x^4) / ((1-x)*(1 - 34*x + x^2)*(1 + 34*x + x^2)). - _R. J. Mathar_, Nov 27 2011
%e A144941 a(1) = 1 because 6*1 - 1 = 5 = A144796(1).
%t A144941 LinearRecurrence[{1,1154,-1154,-1,1},{1,36,753,41348,868769},30] (* _Harvey P. Dale_, Dec 27 2018 *)
%o A144941 (PARI) Vec(-x*(1+35*x-437*x^2+205*x^3+4*x^4) / ((x-1)*(x^2-34*x+1)*(x^2+34*x+1)) + O(x^30)) \\ _Colin Barker_, Dec 22 2014
%o A144941 (Magma) R<x>:=PowerSeriesRing(Integers(), 30); Coefficients(R!( x*(1+ 35*x-437*x^2+205*x^3+4*x^4)/((1-x)*(1-34*x+x^2)*(1+34*x+x^2)) )); // _G. C. Greubel_, Mar 16 2019
%o A144941 (Sage) a=(x*(1+ 35*x-437*x^2+205*x^3+4*x^4)/((1-x)*(1-34*x+x^2)*(1+34*x +x^2))).series(x, 30).coefficients(x, sparse=False); a[1:] # _G. C. Greubel_, Mar 16 2019
%o A144941 (GAP) a:=[1,36,753,41348,868769];; for n in [6..30] do a[n]:=a[n-1] +1154*a[n-2]-1154*a[n-3]-a[n-4]+a[n-5]; od; a; # _G. C. Greubel_, Mar 16 2019
%Y A144941 Cf. A133301, A144796, A144797.
%K A144941 easy,nonn
%O A144941 1,2
%A A144941 _Richard Choulet_, Sep 26 2008
%E A144941 a(6) corrected and sequence extended by _R. J. Mathar_, Nov 27 2011