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Search: id:A123757
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| A123757 |
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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). |
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+0
2
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| 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)
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OFFSET
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0,3
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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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.
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MATHEMATICA
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f[l_List] := Append[l, Plus @@ Select[l, Mod[ #, Plus @@ IntegerDigits[Length[l], 2]] == 0 &]]; Nest[f, {1}, 40] (*Chandler*)
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CROSSREFS
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Cf. A123755.
Sequence in context: A054227 A054228 A044044 this_sequence A167399 A019310 A014113
Adjacent sequences: A123754 A123755 A123756 this_sequence A123758 A123759 A123760
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KEYWORD
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easy,nonn
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AUTHOR
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Leroy Quet Oct 12 2006
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 16 2006
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