OFFSET
0,2
FORMULA
a(n)= Sum_{j=1..n} |[Sum_{i=1..j} M(i,j) + Sum_{i=1..j} M(j,i) - M(j,j)](-1)^j| Let b(n) be the numbers of the sequence A123326: a(n)= b(n)+2*[(-1)^(n+1)]*Sum_{i=n-1..1} b(i) for n even a(n)= b(n)+2*[(-1)^n]*Sum_{i=n-1..1} b(i) for n odd
EXAMPLE
a(4)= 1+2+3+4+1+2+1 - (1+2+3+1+1) + (1+2+1) - 1 = 9
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paolo P. Lava and Giorgio Balzarotti, Sep 26 2006
STATUS
approved