A121896 Let M be the matrix defined in A111490. Sequence gives M(1,1), M(1,2)+M(1,2)+M(2,2), M(1,3)+M(2,3)+M(3,1)+M(3,2)+M(3,3), etc.

1, 4, 8, 14, 20, 30, 37, 51, 61, 76, 89, 111, 120, 146, 165, 187, 205, 239, 255, 293, 312, 344, 375, 421, 434, 479, 516, 558, 587, 645, 664, 726, 760, 812, 861, 919, 937, 1011, 1066, 1128, 1159, 1241, 1272, 1358, 1407, 1465, 1532, 1626, 1647, 1738, 1796, 1878

Offset

1,2

Links

Table of n, a(n) for n=1..52.

Formula

a(n) = -M(n,n) + Sum_{i=1..n} (M(i,n) + M(n,i)).

Example

a(4) = 1+2+1+1+2+3+4 = 14.

Crossrefs

Cf. A111490.

Sequence in context: A265284 A055507 A343880 * A368610 A173290 A312686

Adjacent sequences: A121893 A121894 A121895 * A121897 A121898 A121899

Keyword

easy,nonn

Author

Paolo P. Lava and Giorgio Balzarotti, Sep 01 2006

Status

approved