OFFSET
1,2
LINKS
Alois P. Heinz, Antidiagonals n = 1..141, flattened
Ana Rechtman, 3ème Défi du Calendrier Mathématique, Images des Mathématiques, CNRS, January 2017.
EXAMPLE
For n=2 and k=3, the matrix will be
1 2 3 and 1 3 5
4 5 6 2 4 6
and there are 2 identical terms, 1 and 6, whose sum is 7.
The triangle begins
1;
3, 5;
6, 7, 15;
10, 9, 13, 34;
15, 11, 24, 21, 65;
21, 13, 19, 25, 31, 111;
...
MAPLE
T:= (n, k)-> add(add(`if`(j+k*(i-1)=
i+n*(j-1), j+k*(i-1), 0), i=1..n), j=1..k):
seq(seq(T(n, k), k=1..n), n=1..20); # Alois P. Heinz, Jan 28 2017
PROG
(PARI) a(n, k) = {ml = matrix(n, k, i, j, ((i-1)*k+j)); mc = matrix(n, k, i, j, ((j-1)*n+i)); sum(i=1, n, sum(j=1, k, ml[i, j]*(ml[i, j] == mc[i, j]))); }
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Michel Marcus, Jan 28 2017
STATUS
approved