OFFSET
1,2
LINKS
FORMULA
S(n; t, s) = S(n-1; t, s) + S(n-1; t+3, s+3t+1) + S(n-1; t+2, s+2t) + S(n-1; t+1, s+t+1).
Empirical g.f.: x*(1-8*x+24*x^2-24*x^3-24*x^4+32*x^5+64*x^6-192*x^7) / ((1-2*x)*(1-4*x)*(1-4*x+8*x^2)*(1+16*x^4)). - Colin Barker, Feb 21 2016
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Frank Ruskey, Mar 29 2002
EXTENSIONS
Terms a(11) onward from Max Alekseyev, Apr 09 2013
STATUS
approved