login
A123328
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.
0
1, 3, 5, 9, 11, 19, 18, 33, 28, 48, 41, 70, 50, 96, 69, 118, 87, 152
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
Sequence in context: A059819 A074986 A307435 * A226175 A091945 A212288
KEYWORD
easy,nonn
AUTHOR
STATUS
approved