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 A036226 #21 Sep 08 2022 08:44:52
%S A036226 1,49,1372,28812,504210,7764834,108707676,1413199788,17311697403,
%T A036226 201969803035,2262061793992,24471395771368,256949655599364,
%U A036226 2628792630362724,26287926303627240,257621677775546952
%N A036226 Expansion of 1/(1-7*x)^7.
%C A036226 With a different offset, number of n-permutations (n >= 6) of 8 objects: r, s, t, u, v, z, x, y with repetition allowed, containing exactly six (6) u's. - _Zerinvary Lajos_, Jun 16 2008
%H A036226 Vincenzo Librandi, <a href="/A036226/b036226.txt">Table of n, a(n) for n = 0..400</a>
%H A036226 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (49, -1029, 12005, -84035, 352947, -823543, 823543).
%F A036226 a(n) = 7^n*binomial(n+6, 6).
%F A036226 G.f.: 1/(1-7*x)^7.
%F A036226 a(n) = 49*a(n-1) - 1029*a(n-2) + 12005*a(n-3) - 84035*a(n-4) + 352947*a(n-5) - 823543*a(n-6) + 823543*a(n-7), a(0)=1, a(1)=49, a(2)=1372, a(3)=28812, a(4)=504210, a(5)=7764834, a(6)=108707676. - _Harvey P. Dale_, Feb 21 2013
%p A036226 seq(binomial(n+6,6)*7^n,n=0..16); # _Zerinvary Lajos_, Jun 16 2008
%t A036226 CoefficientList[Series[1/(1-7x)^7,{x,0,20}],x] (* or *) LinearRecurrence[ {49,-1029,12005,-84035,352947,-823543,823543},{1,49,1372,28812,504210,7764834,108707676},20] (* _Harvey P. Dale_, Feb 21 2013 *)
%o A036226 (Sage)[lucas_number2(n, 7, 0)*binomial(n,6)/7^6 for n in range(6, 22)] # _Zerinvary Lajos_, Mar 13 2009
%o A036226 (Magma) [7^n* Binomial(n+6, 6): n in [0..20]]; // _Vincenzo Librandi_, Oct 12 2011
%Y A036226 Cf. A036084.
%K A036226 nonn,easy
%O A036226 0,2
%A A036226 _Wolfdieter Lang_