A108165 a(n)=a(n-1) +A108173(n+1) -A108173(n).

2, 5, 9, 12, 15, 19, 22, 26, 29, 32, 36, 39, 42, 46, 49, 53, 56, 59, 63, 66, 70, 73, 76, 80, 83, 86, 90, 93, 97, 100, 103, 107, 110, 114, 117, 120, 124, 127, 130, 134, 137, 141, 144, 147, 151, 154, 157, 161, 164, 168, 171, 174, 178, 181, 185, 188, 191, 195, 198, 201

Offset: 1

Author

Roger L. Bagula, Jun 13 2005

Keywords

• nonn

Comments

Tribonacci version of A001950 using beta, the positive real root of x^3-x^2-x-1, as the constant.

Crossrefs

Cf. A007066, A076662, A001950.

Programs

Mathematica

NSolve[x^3 - x^2 - x - 1 = 0, x] beta = 1.8392867552141612 a[n_] = 1 + Ceiling[(n - 1)*beta^2] (* A007066-like*) aa = Table[a[n], {n, 1, 100}] (*A076662-like*) b = Table[a[n] - a[n - 1], {n, 2, Length[aa]}] F[1] = 2; F[n_] := F[n] = F[n - 1] + b[[n]] (* A000195-like*) c = Table[F[n], {n, 1, Length[b] - 1}]

Extensions

Partially edited by N. J. A. Sloane, May 04 2007

Correction of definition and offset by R. J. Mathar, Mar 12 2012