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 A258808 #24 Jan 09 2025 15:04:21
%S A258808 0,127,2186,16383,78124,279935,823542,2097151,4782968,9999999,
%T A258808 19487170,35831807,62748516,105413503,170859374,268435455,410338672,
%U A258808 612220031,893871738,1279999999,1801088540,2494357887,3404825446,4586471423,6103515624,8031810175
%N A258808 a(n) = n^7 - 1.
%H A258808 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (8,-28,56,-70,56,-28,8,-1).
%F A258808 G.f.: x^2*(127 + 1170*x + 2451*x^2 + 1156*x^3 + 141*x^4 - 6*x^5 + x^6)/(1 - x)^8.
%F A258808 a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8).
%F A258808 a(n) = -A024005(n). [_Bruno Berselli_, Jun 11 2015]
%F A258808 a(n) = (n-1)*A053716(n). - _Michel Marcus_, Aug 21 2015
%t A258808 Table[n^7 - 1, {n, 1, 40}] (* or *) LinearRecurrence[{8, -28, 56, -70, 56, -28, 8, -1}, {0, 127, 2186, 16383, 78124, 279935, 823542, 2097151}, 40]
%o A258808 (Magma) [n^7-1: n in [1..40]];
%o A258808 (Magma) I:=[0,127,2186,16383, 78124,279935,823542,2097151]; [n le 8 select I[n] else 8*Self(n-1) - 28*Self(n-2)+56*Self(n-3)-70*Self(n-4)+56*Self(n-5) - 28*Self(n-6) +8*Self(n-7)-Self(n-8): n in [1..40]];
%o A258808 (Sage) [n^7-1 for n in (1..40)] # _Bruno Berselli_, Jun 11 2015
%Y A258808 Subsequence of A181126.
%Y A258808 Cf. A258806.
%Y A258808 Cf. similar sequences listed in A258807.
%K A258808 nonn,easy
%O A258808 1,2
%A A258808 _Vincenzo Librandi_, Jun 11 2015