OFFSET
1,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 1..500
FORMULA
Product_{k>=1} (1+a(k)*x^k) = 1 + Sum_{k>=1} k*x^k. - Seiichi Manyama, Jun 24 2018
EXAMPLE
From the positive integers 1,2,3,..., construct the series 1+x+2x^2+3x^3+4x^4+... a(1) is always the coefficient of x, here 1. Divide by (1+a(1)x), i.e. here (1+x), to get the quotient (1+a(2)x^2+...), which here gives a(2)=2. Then divide this quotient by (1+a(2)x^2), i.e. here (1+2x^2), to get (1+a(3)x^3+...), giving a(3)=1.
CROSSREFS
KEYWORD
sign
AUTHOR
Neil Fernandez, Nov 09 2008
EXTENSIONS
More terms from Seiichi Manyama, Jun 23 2018
STATUS
approved