A074079 Square array A(row,col) (listed in order A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), A(0,3), etc.), giving essentially the same information as the triangle A074080 which shows only the upper triangular region.

1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 2, 1, 0, 0, 0, 0, 0, 0, 3, 2, 0, 0, 0, 0, 0, 0, 1, 3, 5, 1, 0, 0, 0, 0, 0, 0, 1, 3, 10, 3, 0, 0, 0, 0, 0, 0, 0, 0, 3, 17, 9, 1, 0, 0, 0, 0, 0, 0, 0, 1, 5, 28, 24, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 41, 57, 14, 1, 0, 0, 0

Offset: 0

Author

Antti Karttunen, Aug 19 2002

Keywords

• nonn
• tabl

Crossrefs

Obtained from the square array A073346 by dividing the entries on the k-th row by 2^k. Column sums: A073431. See A074080 for explanation. Cf. also A025581, A002262.

Programs

Maple

A074079bi := (n,k) -> A073346bi(n,k)/(2^k);
A074079 := n -> A074079bi(A025581(n), A002262(n));
A025581 := n -> binomial(1+floor((1/2)+sqrt(2*(1+n))),2) - (n+1);
A002262 := n -> n - binomial(floor((1/2)+sqrt(2*(1+n))),2);

Formula

A074079(n, k) = A073346(n, k)/(2^k)