A124063 a(1)=a(2)=1. a(n) = the sum of the terms, from among the first (n-2) terms of the sequence, which divide a(n-1).

1, 1, 1, 2, 3, 3, 6, 11, 3, 9, 12, 20, 5, 3, 12, 35, 8, 5, 8, 13, 3, 15, 28, 5, 13, 16, 21, 18, 35, 53, 3, 18, 56, 49, 3, 21, 45, 63, 75, 54, 77, 14, 5, 18, 77, 91, 29, 3, 24, 75, 137, 3, 27, 39, 56, 119, 3, 30, 76, 5, 23, 3, 33, 47, 3, 36, 134, 5, 28, 47, 50, 35, 103, 3, 39, 107, 3, 42

Offset: 1

Author

Leroy Quet, Nov 04 2006

Keywords

• nonn

Comments

First occurrence of k or 0 if not present: 1,4,5,0,13,7,0,17,10,0,8,11,20,42,22,26,0,28,220,12. - Robert G. Wilson v, Nov 04 2006

Examples

			a(11)= 12. Among the first 10 terms of the sequence a(1)=1, a(2)=1, a(3)=1, a(4)=2, a(5)=3, a(6)=3, a(7)=6 and a(9)=3 each divide 12. So a(12) = 1+1+1+2+3+3+6+3 = 20.
		

Programs

Mathematica

f[ s_ ] := Append[ s, Plus @@ Select[ Most@s, Mod[ s[ [ -1 ] ], # ] == 0 & ] ];; Nest[ f, {1, 1}, 76 ] (* Robert G. Wilson v *)

Extensions

More terms from Robert G. Wilson v, Nov 04 2006