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 A138999 #10 Feb 21 2018 16:54:22
%S A138999 1,1,1,1,1,1,10,2,2,2,2,2,2,18,3,3,3,3,3,3,26,4,4,4,4,4,4,34,5,5,5,5,
%T A138999 5,5,42,6,6,6,6,6,6,50,7,7,7,7,7,7,58,8,8,8,8,8,8,66,9,9,9,9,9,9,74,
%U A138999 10,10,10,10,10,10,82,11,11,11,11,11,11,90,12,12,12,12,12,12,98,13,13,13,13
%N A138999 First differences of Frobenius numbers for 8 successive numbers A138988.
%C A138999 For first differences of Frobenius numbers for 2 successive numbers see A005843
%C A138999 For first differences of Frobenius numbers for 3 successive numbers see A014682
%C A138999 For first differences of Frobenius numbers for 4 successive numbers see A138995
%C A138999 For first differences of Frobenius numbers for 5 successive numbers see A138996
%C A138999 For first differences of Frobenius numbers for 6 successive numbers see A138997
%C A138999 For first differences of Frobenius numbers for 7 successive numbers see A138998
%C A138999 For first differences of Frobenius numbers for 8 successive numbers see A138999
%H A138999 Harvey P. Dale, <a href="/A138999/b138999.txt">Table of n, a(n) for n = 1..1000</a>
%F A138999 a(n) = A138988(n+1) - A138988(n).
%F A138999 From _R. J. Mathar_, Apr 20 2008: (Start)
%F A138999 G.f.: -(-1-x-x^2-x^3-x^4-x^5-10*x^6+2*x^13)/((x-1)^2*(x^6+x^5+x^4+x^3+x^2+x+1)^2).
%F A138999 a(n) = 2*a(n-7) - a(n-14).
%F A138999 (End)
%F A138999 a(n) = -(1/7)*mod(n,7)*x(7+mod(n,7))+(1/7)*mod(n,7)*x(mod(n,7))+x(mod(n,7))-(1/7)*n *x(mod(n,7))+(1/7)*n*x(7+mod(n,7)). - _Alexander R. Povolotsky_, Apr 20 2008
%t A138999 a = {}; Do[AppendTo[a, FrobeniusNumber[{n + 1, n + 2, n + 3, n + 4, n + 5, n + 6, n + 7, n + 8}]], {n, 1, 100}]; Differences[a]
%t A138999 Differences[Table[FrobeniusNumber[Range[n,n+7]],{n,2,90}]] (* _Harvey P. Dale_, Oct 02 2011 *)
%Y A138999 Cf. A028387, A037165, A079326, A138985, A138986, A138987, A138988, A138989, A138990, A138991, A138992, A138993, A138994, A138995, A138996, A138997, A138998, A138999.
%K A138999 nonn
%O A138999 1,7
%A A138999 _Artur Jasinski_, Apr 05 2008