A157124 a(1)=1; a(n) = floor((n-1)*Sum_{k=1..n-1} 1/a(k)).

1, 1, 4, 6, 9, 12, 15, 18, 21, 25, 28, 31, 34, 37, 41, 44, 47, 51, 54, 57, 61, 64, 68, 71, 75, 78, 82, 85, 89, 92, 96, 99, 103, 106, 110, 113, 117, 120, 124, 128, 131, 135, 138, 142, 146, 149, 153, 157, 160, 164, 168, 171, 175, 179, 182, 186, 190, 193, 197, 201, 204

Offset

1,3

Links

Vaclav Kotesovec, Table of n, a(n) for n = 1..10000

Example

For n = 5, (5-1)*(1 + 1 + 1/4 + 1/6) = 4*29/12 = 29/3. So a(5) = floor(29/3) = 9.

Maple

a[1] := 1: for n to 65 do a[n+1] := floor(n*(sum(1/a[k], k = 1 .. n))) end do: seq(a[n], n = 1 .. 65); # Emeric Deutsch, Mar 01 2009

Mathematica

a[1] = 1; a[n_] := a[n] = Floor[(n - 1)*Sum[1/a[k], {k, 1, n - 1}]]; Table[a[n], {n, 1, 100}] (* Vaclav Kotesovec, Apr 26 2020 *)

Crossrefs

Sequence in context: A054087 A079255 A171845 * A162735 A024675 A274135

Adjacent sequences: A157121 A157122 A157123 * A157125 A157126 A157127

Keyword

nonn

Author

Leroy Quet, Feb 23 2009

Extensions

More terms from Emeric Deutsch, Mar 01 2009

Status

approved