OFFSET
0,4
REFERENCES
Koh, Youngmee, and Sangwook Ree. "Connected permutation graphs." Discrete Mathematics 307.21 (2007): 2628-2635. See page 2631.
FORMULA
E.g.f.: A(x) = 1+x - Sum_{n>=1} log(1+x)^[n*phi^2] / [n*phi^2]!, where [n*phi^2] = A001950(n), the upper Wythoff sequence.
EXAMPLE
PROG
(PARI) {a(n)=local(phi=(sqrt(5)+1)/2, A=1+x+x*O(x^n)); for(i=1, n, A=1+sum(k=1, n, log(1+x+x*O(x^n))^floor(k*phi)/floor(k*phi)!+x*O(x^n))); n!*polcoeff(A, n)}
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Jan 22 2011
STATUS
approved