OFFSET
1,2
FORMULA
a(n) = Sum_{i=1..n} Sum_{j=1..n} M(i,j).
a(n) = a(n-1) + A121896(n) with a(0)=0.
EXAMPLE
a(4) = 1+1+1+1 + 1+2+1+2 + 1+2+3+1 + 1+2+3+4 = 27.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paolo P. Lava and Giorgio Balzarotti, Sep 26 2006
STATUS
approved