A137789 a(n) = 7^n - 6^n - 5^n - 4^n - 3^n - 2^n.

127, 4607, 50479, 446783, 3622207, 28040447, 211134799, 1561328063, 11403051487, 82538901887, 593482158319, 4245770823743, 30254894691967, 214923605948927, 1522969836817039, 10770185918341823, 76039637426447647, 536127667775741567

Offset: 4

Author

Vladimir Joseph Stephan Orlovsky, Apr 28 2008

Keywords

• nonn
• easy

Comments

For n < 4, a(n) are negative and not entered here. - Michel Marcus, Nov 16 2013

Links

• Index entries for linear recurrences with constant coefficients, signature (27,-295,1665,-5104,8028,-5040).

Programs

Maple

A137789:=n->7^n-6^n-5^n-4^n-3^n-2^n; seq(A137789(n), n=4..50); # Wesley Ivan Hurt, Nov 15 2013

Mathematica

Table[7^n - 6^n - 5^n - 4^n - 3^n - 2^n, {n, 4, 30}] (* Stefan Steinerberger, May 02 2008 *)

Formula

G.f.: x^4*(488880*x^5-572076*x^4+231460*x^3-36445*x^2+1178*x+127)/((2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)*(7*x-1)). - Colin Barker, Nov 05 2012

a(n) = A000420(n) - A001553(n) + 1. - Michel Marcus, Nov 16 2013

Extensions

More terms from Stefan Steinerberger, May 02 2008