A030429 a(n+2) = 7*a(n+1) - 7*a(n) - 9*n; a(n+4) = 9*a(n+3) - 22*a(n+2) + 21*a(n+1) - 7*a(n).

1, 2, 7, 26, 115, 596, 3331, 19100, 110329, 638540, 3697405, 21411974, 124001893, 718129334, 4158891979, 24085338398, 139485124807, 807798504728, 4678193659303, 27092766081872, 156902006957821

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Comments

Hypothetical numbers of terms in general expressions for Lovelock tensors. Hypothetical extension of sequence A006373 - C. C. Briggs (ccb104(AT)psu.edu)

Links

• C. C. Briggs, Some Possible Features of General Expressions for Lovelock Tensors ...
• Index entries for linear recurrences with constant coefficients, signature (9,-22,21,-7).

Crossrefs

Cf. A006373.

Programs

Mathematica

LinearRecurrence[{9,-22,21,-7},{1,2,7,26},30] (* Harvey P. Dale, Oct 12 2015 *)

Formula

Expansion of (1-7*x+11*x^2-14*x^3)/((1-7*x+7*x^2)*(x-1)^2).

a(n) = 2*(23*A030240(n)-133*A030240(n-1)) -9*n -45. - R. J. Mathar, Mar 14 2011