A158095 G.f.: A(x) = exp( Sum_{n>=1} 2*sigma(n,n-1)*x^n/n ).

1, 2, 5, 14, 61, 370, 3454, 40880, 614346, 10848514, 222870183, 5175100204, 134514302384, 3859406052466, 121274242936381, 4139268759072626, 152532132931199062, 6034430112251517608, 255114747410233804986

Offset: 0

Author

Paul D. Hanna, Mar 20 2009

Keywords

• nonn

Examples

			G.f.: A(x) = 1 + 2*x + 5*x^2 + 14*x^3 + 61*x^4 + 370*x^5 +...
		

Crossrefs

Cf. A023881, A294645.

Programs

PARI

a(n)=polcoeff(exp(sum(m=1,n,2*sigma(m,m-1)*x^m/m)+x*O(x^n)),n)