A113978 a(n)=Sum(d|n)(10^(n-d)).

1, 11, 101, 1101, 10001, 111001, 1000001, 11010001, 101000001, 1100100001, 10000000001, 111101000001, 1000000000001, 11000010000001, 101010000000001, 1101000100000001, 10000000000000001, 111001001000000001

Offset: 0

Author

Paul Barry, Nov 11 2005

Keywords

• easy
• nonn

Comments

A074854 in base 2. Stacking the elements gives the triangle A051731.

Programs

PARI

a(n)=if(n<1,0,10^n*polcoeff(sum(k=1,n,10/(10-x^k),x*O(x^n)),n))

Formula

G.f.: Sum_{k>0} 10^(k-1)*x^k/(1-10^(k-1)*x^k).