OFFSET
1,1
LINKS
Christian Sievers, Table of n, a(n) for n = 1..7
Eric Weisstein's World of Mathematics, Maximum Independent Vertex Set
Eric Weisstein's World of Mathematics, Sierpinski Tetrahedron Graph
PROG
(PARI) rd(p)=if(p, pollead(p)*x^poldegree(p), 0);
a(n)={my(s=[1, x, 0, 0, 0]); for(k=2, n, s=vector(5, i, sum(wx=0, 1, sum(wy=0, 1, sum(wz=0, 1, sum(xy=0, 1, sum(xz=0, 1, sum(yz=0, 1, rd(s[1+(i>1)+wx+wy+wz]*s[1+(i>2)+wx+xy+xz]*s[1+(i>3)+wy+xy+yz]*s[1+(i>4)+wz+xz+yz])/x^(wx+wy+wz+xy+xz+yz))))))))); pollead([1, 4, 6, 4, 1]*s~)} \\ Christian Sievers, Jul 21 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Jan 26 2023
EXTENSIONS
a(5) and beyond from Christian Sievers, Jul 21 2024
STATUS
approved