OFFSET
0,1
COMMENTS
a(6) has 104 decimal digits. - Andrew Howroyd, Aug 31 2025
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..8
Eric Weisstein's World of Mathematics, Dominating Set.
Eric Weisstein's World of Mathematics, Dorogovtsev-Goltsev-Mendes Graph.
MATHEMATICA
Join[{3}, Map[{1, 2, 1} . # &, NestList[Function[{p2, q1, q2}, {p2 (p2^2 + q1^2), q1^2 (q2 + p2), q2 (q1^2 + q2^2)}] @@ # &, {1, 2, 2}, 7]]] (* Eric W. Weisstein, Sep 03 2025 *)
PROG
(PARI)
step(v)={my([p2, q1, q2]=v); [p2*(p2^2+q1^2), q1^2*(q2+p2), q2*(q1^2+q2^2)]}
a(n)={if(n==0, 3, my(v=[1, 2, 2]); for(i=2, n, v=step(v)); v[1]+2*v[2]+v[3])} \\ Andrew Howroyd, Aug 31 2025
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Aug 29 2025
EXTENSIONS
a(4) onwards from Andrew Howroyd, Aug 29 2025
STATUS
approved
