A174938 a(n) = Sum_{k<=n} A007955(k) * A007955(n-k+1), where A007955(m) = product of divisors of m.

1, 4, 10, 28, 51, 140, 252, 452, 953, 1164, 2974, 5676, 13531, 14828, 40744, 27260, 146845, 55372, 288174, 177700, 574867, 204916, 3721652, 988332, 3550621, 3267452, 11129590, 4173196, 46286551, 7402156

Offset

1,2

Links

Table of n, a(n) for n=1..30.

Example

For n = 4, A007955(n) = b(n): a(4) = b(1)*b(4) + b(2)*b(3) + b(3)* b(2) + b(4)*b(1) = 1*8 + 2*3 + 3*2 + 8*1 = 28.

Crossrefs

Sequence in context: A222963 A333172 A257028 * A032248 A092504 A340568

Adjacent sequences: A174935 A174936 A174937 * A174939 A174940 A174941

Keyword

nonn

Author

Jaroslav Krizek, Apr 02 2010

Status

approved