A130618 a(1)=1; a(n+1) = Sum_{k=0..a(n) mod n} a(n-k).

1, 1, 2, 4, 4, 12, 12, 35, 63, 63, 173, 368, 734, 1448, 2884, 5607, 11340, 16947, 39627, 79301, 118928, 271750, 543500, 1092066, 2184858, 4358317, 8727848, 17455759, 34911652, 61095259, 130918366, 244381036, 506138640, 1012353685, 2024551664

Offset: 1

Author

Leroy Quet, Jun 18 2007

Keywords

• nonn

Examples

			a(10) mod 10 = 63 mod 10 = 3. So a(11) = Sum_{k=0..3} a(10-k) = a(10) + a(9) + a(8) + a(7) = 63 + 63 + 35 + 12 = 173.
		

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 1..3300
• Vaclav Kotesovec, Plot of a(n) / (2^n/n) for n = 1..50000

Crossrefs

Cf. A057176.

Programs

Maple

a[1] := 1; for n to 35 do a[n+1] := add(a[n-k], k = 0 .. `mod`(a[n], n)) end do; seq(a[n], n = 1 .. 35); # Emeric Deutsch, Jun 21 2007

Mathematica

a[1] = 1; a[n_] := a[n] = Sum[a[n-1-k], {k, 0, Mod[a[n-1], n-1]}]; Table[a[n], {n, 1, 50}] (* Vaclav Kotesovec, Apr 26 2020 *)

Extensions

More terms from Jon E. Schoenfield, Jun 21 2007

More terms from Emeric Deutsch, Jun 21 2007