%I #20 Mar 11 2024 05:58:51
%S 1,2,3,9,11,13,23,26,29,43,47,51,69,74,79,101,107,113,139,146,153,183,
%T 191,199,233,242,251,289,299,309,351,362,373,419,431,443,493,506,519,
%U 573,587,601,659,674,689,751,767,783,849,866,883,953,971,989,1063,1082
%N a(n) = Frobenius number for 4 successive numbers = F(n+1, n+2, n+3, n+4).
%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,2,-2,0,-1,1).
%F G.f.: x*(x^6-4*x^3-x^2-x-1) / ((x-1)^3*(x^2+x+1)^2). [_Colin Barker_, Dec 13 2012]
%e a(4) = 9 because 9 is the largest number k such that the equation 5*x_1 + 6*x_2 + 7*x_3 + 9*x_4 = k has no solution for any nonnegative x_i (in other words, for every k > 9 there exist one or more solutions).
%t Table[FrobeniusNumber[{n + 1, n + 2, n + 3, n + 4}], {n, 1, 100}]
%Y Frobenius number for k successive numbers: A028387 (k=2), A079326 (k=3), this sequence (k=4), A138985 (k=5), A138986 (k=6), A138987 (k=7), A138988 (k=8).
%K nonn,easy
%O 1,2
%A _Artur Jasinski_, Apr 05 2008