A192253 1-sequence of reduction of (n!) by x^2 -> x+1.

0, 1, 3, 15, 87, 687, 6447, 71967, 918687, 13256607, 212840607, 3765435807, 72741666207, 1523637512607, 34389853295007, 832071217775007, 21482864837231007, 589515687506543007, 17133249343107695007, 525731414152434287007, 16984313499467403887007

Offset: 1

Author

Clark Kimberling, Jun 27 2011

Keywords

• nonn

Comments

See A192232 for definition of "k-sequence of reduction of [sequence] by [substitution]". After the tenth term, the final digit is 7, for terms in both A192253 and A192252. After the 100th term, the final 6 digits of terms in A192253 are 5,6,7,0,0,7.

Crossrefs

Cf. A192252, A192232.

Programs

Mathematica

(See A192252.)

Formula

Conjecture: a(n) -n*a(n-1) -(n-1)*(n-3)*a(n-2) +(n-1)*(n-2)*a(n-3)=0. - R. J. Mathar, May 04 2014

Conjecture: partial sums of A005443. - Sean A. Irvine, Jul 12 2022