A074801 a(n) is the sum of the n-th row of the triangle formed by replacing each m in Pascal's triangle with sigma(m).

1, 2, 5, 10, 28, 50, 116, 178, 528, 1282, 2794, 4778, 10594, 17166, 33426, 60242, 183072, 304202, 759716, 1288642, 2965286, 6352098, 11776586, 18326642, 48714362, 95769336, 172377654, 417138342, 1004225842, 1633822142, 3266821106, 4706920002, 16520601024

Offset

0,2

Links

Robert G. Wilson v, Table of n, a(n) for n = 0..3000

Formula

a(n) >= 2^n with equality for n <= 2. - Michel Marcus, Mar 19 2017

Example

The third row of Pascal's triangle is 1 3 3 1. When each n here is replaced by sigma(n), the row becomes 1 4 4 1 with a sum of 10, so a(3) = 10.

Mathematica

a[n_] := Sum[DivisorSigma[1, Binomial[n, i]], {i, 0, n}]; Table[a[i], {i, 1, 21}]

Prog

(PARI) a(n) = sum(k=0, n, sigma(binomial(n, k))); \\ Michel Marcus, Mar 17 2017

Crossrefs

Cf. A000079, A000203, A007318.

Sequence in context: A032099 A243797 A120896 * A324838 A370316 A257889

Adjacent sequences: A074798 A074799 A074800 * A074802 A074803 A074804

Keyword

easy,nonn

Author

Joseph L. Pe, Sep 30 2002

Extensions

More terms from Carl Najafi, Oct 10 2011

Offset changed to 0 by Editors, Mar 19 2017

Status

approved