OFFSET
1,2
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..10000
FORMULA
G.f.: x/(1 - x) + Sum_{i>=1} i*x^(i+1)/(1 - x) * Product_{j=1..i} 1/(1 - x^j). - Ilya Gutkovskiy, Apr 04 2017
a(n) ~ exp(Pi*sqrt(2*n/3)) * (log(6*n) + 2*gamma - 2*log(Pi)) * sqrt(3) / (4*Pi^2), where gamma is the Euler-Mascheroni constant (A001620). - Vaclav Kotesovec, May 19 2018
EXAMPLE
MAPLE
A008284 := proc(n, k) if n >= 1 and n = k or k = 1 then 1 elif k > n then 0 else add( A008284(n-k, i), i=1..k) ; fi ; end: A006128 := proc(n) add( k*A008284(n, k), k=1..n) ; end: a := 1 : printf("%d, ", a) ; for n from 2 to 80 do a := a + A006128(n-1) : printf("%d, ", a) ; od : # R. J. Mathar, Jan 13 2007
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Alford Arnold, Nov 13 2006
EXTENSIONS
More terms from R. J. Mathar, Jan 13 2007
Clarification of name from Ilya Gutkovskiy, Apr 04 2017
STATUS
approved