OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..80
EXAMPLE
L.g.f.: A(x) = x + 3*x^2/2 + 19*x^3/3 + 223*x^4/4 + 4771*x^5/5 +...
A(x) = log(1 + x + 2x^2 + 8x^3 + 64x^4 + 1024x^5 +...+ 2^(n(n-1)/2)*x^n +...).
MATHEMATICA
max = 14; s = Log[Sum[2^(k*(k-1)/2)*x^k, {k, 0, max}]] + O[x]^(max+1); CoefficientList[s, x]*Range[0, max] // Rest (* Jean-François Alcover, Sep 03 2017 *)
PROG
(PARI) a(n)=n*polcoeff(log(sum(k=0, n, 2^(k*(k-1)/2)*x^k +x*O(x^n))), n)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 15 2008
STATUS
approved