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

1,3

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

Example

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.

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 *)

Crossrefs

Cf. A057176.

Sequence in context: A000936 A319594 A065449 * A129882 A129017 A086915

Adjacent sequences: A130615 A130616 A130617 * A130619 A130620 A130621

Keyword

nonn

Author

Leroy Quet, Jun 18 2007

Extensions

More terms from Jon E. Schoenfield, Jun 21 2007

More terms from Emeric Deutsch, Jun 21 2007

Status

approved