|
Search: id:A123757
|
|
|
| A123757 |
|
a(0)=1. a(n) = sum of the earlier terms which are divisible by (the number of 1's in the binary representation of n). |
|
+0
2
|
|
| 1, 1, 2, 2, 6, 10, 20, 6, 48, 94, 188, 60, 436, 120, 240, 1112, 2346, 4690, 9380, 2826, 21586, 5652, 11304, 28560, 88688, 51168, 102336, 299312, 204672, 803296, 1606592, 43080, 3287834, 6575666, 13151332, 452424, 26755088, 904848, 1809696, 46329652
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
EXAMPLE
|
9 in binary is 1001, which has 2 ones. So a(9) is the sum of terms, from a(0) to are divisible by 2. a(2)=2, a(3)=2, a(4)=6, a(5)=10, a(6)=20, a(7)=6, and a(8)=48 are the earlier terms which are divisible by 2. So a(9) = 2+2+6+10+20+6+48 = 94.
|
|
MATHEMATICA
|
f[l_List] := Append[l, Plus @@ Select[l, Mod[ #, Plus @@ IntegerDigits[Length[l], 2]] == 0 &]]; Nest[f, {1}, 40] (*Chandler*)
|
|
CROSSREFS
|
Cf. A123755.
Sequence in context: A054227 A054228 A044044 this_sequence A019310 A014113 A078008
Adjacent sequences: A123754 A123755 A123756 this_sequence A123758 A123759 A123760
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Leroy Quet (qq-quet(AT)mindspring.com), Oct 12 2006
|
|
EXTENSIONS
|
Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 16 2006
|
|
|
Search completed in 0.002 seconds
|
