OFFSET
1,2
COMMENTS
n < a(n) < A367690(n) for n > 1.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = Sum_{x=1..n} Sum_{y=1..x} A107435(x,y).
a(n) = a(n-1) + 1 + A049826(n) with a(0) = 0. - Alois P. Heinz, Dec 04 2023
MAPLE
g:= proc(x, y) option remember;
`if`(y=0, 0, 1+g(y, irem(x, y)))
end:
a:= proc(n) option remember; `if`(n=0, 0,
a(n-1)+add(g(n, j), j=1..n))
end:
seq(a(n), n=1..100); # Alois P. Heinz, Dec 04 2023
MATHEMATICA
g[x_, y_] := g[x, y] = If[y == 0, 0, 1 + g[y, Mod[x, y]]];
a[n_] := a[n] = If[n == 0, 0, a[n - 1] + Sum[g[n, j], { j, 1, n}]];
Table[a[n], {n, 1, 100}] (* Jean-François Alcover, Mar 08 2024, after Alois P. Heinz *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Darío Clavijo, Dec 04 2023
STATUS
approved