A104074 a(1)=1. a(n) = a(n-1) + (number of terms, from among terms a(1) through a(n-1), which divide Sum_{k=1..n-1} a(k)).

1, 2, 3, 6, 10, 12, 14, 19, 20, 22, 23, 29, 31, 36, 42, 47, 48, 49, 54, 60, 67, 68, 70, 71, 77, 78, 79, 83, 85, 90, 98, 100, 105, 107, 109, 111, 116, 118, 130, 133, 134, 135, 137, 140, 141, 144, 146, 153, 155, 161, 162, 164, 165, 170, 175, 176, 178, 179, 184, 186, 188

Offset

1,2

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Example

The sum of the first 7 terms of the sequence is 48. There are 5 terms from among the first 7 terms which divide 48. (Those terms are a(1)=1, a(2)=2, a(3)=3, a(4)=6, a(6)=12.) So a(8) = a(7) + 5 = 19.

Mathematica

a = {1}, c = 1, Do[AppendTo[a, a[[-1]] + Count[a, _?(Mod[c, #] == 0 &)]]; c += Last[a], {i, 60}]; a (* Michael De Vlieger, Nov 14 2021 *)

Crossrefs

Sequence in context: A189478 A364164 A090695 * A140785 A355177 A038775

Adjacent sequences: A104071 A104072 A104073 * A104075 A104076 A104077

Keyword

nonn

Author

Leroy Quet, Jun 24 2007

Extensions

Corrected and extended by Joshua Zucker, Jul 18 2007

Status

approved