A138999 First differences of Frobenius numbers for 8 successive numbers A138988.

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, 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, 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

Offset: 1

Author

Artur Jasinski, Apr 05 2008

Keywords

• nonn

Comments

For first differences of Frobenius numbers for 2 successive numbers see A005843

For first differences of Frobenius numbers for 3 successive numbers see A014682

For first differences of Frobenius numbers for 4 successive numbers see A138995

For first differences of Frobenius numbers for 5 successive numbers see A138996

For first differences of Frobenius numbers for 6 successive numbers see A138997

For first differences of Frobenius numbers for 7 successive numbers see A138998

For first differences of Frobenius numbers for 8 successive numbers see A138999

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A028387, A037165, A079326, A138985, A138986, A138987, A138988, A138989, A138990, A138991, A138992, A138993, A138994, A138995, A138996, A138997, A138998, A138999.

Programs

Mathematica

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]
Differences[Table[FrobeniusNumber[Range[n,n+7]],{n,2,90}]] (* Harvey P. Dale, Oct 02 2011 *)

Formula

a(n) = A138988(n+1) - A138988(n).

From R. J. Mathar, Apr 20 2008: (Start)

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).

a(n) = 2*a(n-7) - a(n-14).

(End)

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