OFFSET
7,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 7..1000
Index entries for linear recurrences with constant coefficients, signature (9,-25,70,-299,405,-746,2795,-19,3758,-7633,-12165,-17481,-9272,11804,14400,14400).
FORMULA
G.f.: -(120*x^9 +120*x^8 +71*x^7 +296*x^6 +86*x^5 +116*x^4 +32*x^3 +19*x^2 +3*x+1) *x^7 / ((x-1) *(5*x-1) *(3*x-1) *(2*x-1) *(4*x-1) *(x+1) *(x^2+x+1) *(5*x^2+x+1) *(3*x^2+x+1) *(4*x^2+x+1) *(2*x^2+x+1)).
EXAMPLE
a(7) = 1: 1|2|3|4|5|6|7.
a(8) = 12: 14|2|3|5|6|7|8, 15|2|3|4|6|7|8, 1|25|3|4|6|7|8, 16|2|3|4|5|7|8, 1|26|3|4|5|7|8, 1|2|36|4|5|7|8, 1|27|3|4|5|6|8, 1|2|37|4|5|6|8, 1|2|3|47|5|6|8, 1|2|38|4|5|6|7, 1|2|3|48|5|6|7, 1|2|3|4|58|6|7.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Alois P. Heinz, Aug 20 2015
STATUS
approved