cp's OEIS Frontend

A026290 a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, s(1) = 1, s(n) = 4, |s(i) - s(i-1)| <= 1 for i >=2, |s(2) - s(1)| = 1, |s(3) - s(2)| = 1 if s(2) = 1. Also a(n) = T(n,n-4), where T is the array in A026268.

%I A026290 #4 Mar 30 2012 18:56:05
%S A026290 1,4,14,46,145,446,1349,4034,11966,35290,103642,303458,886548,2585922,
%T A026290 7534245,21934524,63826041,185668816,540034074,1570719570,4568920029,
%U A026290 13292253106,38679350746,112583530784,327793747775,954702193796
%N A026290 a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0, s(1) = 1, s(n) = 4, |s(i) - s(i-1)| <= 1 for i >=2, |s(2) - s(1)| = 1, |s(3) - s(2)| = 1 if s(2) = 1. Also a(n) = T(n,n-4), where T is the array in A026268.
%F A026290 G.f.: 32z^4(1-z)(1-z^2)/[1-z+sqrt(1-2z-3z^2)]^5.
%Y A026290 Pairwise sums of A026145.
%Y A026290 Pairwise sums of A026125.
%K A026290 nonn
%O A026290 4,2
%A A026290 _Clark Kimberling_