OFFSET

1,2

LINKS

Eric Weisstein's World of Mathematics, Octagonal Number

EXAMPLE

From Seiichi Manyama, May 16 2021: (Start)

Let S(k, m) denote the sum of m octagonal numbers starting from k*(3*k-2). We have

a(1) = S(1, 1);

a(2) = S(19, 1) = S(1, 10);

a(3) = S(45, 1) = S(11, 9) = S(1, 18). (End)

CROSSREFS

KEYWORD

nonn,hard,more

AUTHOR

Ilya Gutkovskiy, Apr 12 2020

STATUS

approved