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Search: id:A074330
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| A074330 |
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a(n)=sum(k=1,n,2^b(k)) where b(k) denotes the number of 1's in the binary representation of k. |
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+0
4
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| 2, 4, 8, 10, 14, 18, 26, 28, 32, 36, 44, 48, 56, 64, 80, 82, 86, 90, 98, 102, 110, 118, 134, 138, 146, 154, 170, 178, 194, 210, 242, 244, 248, 252, 260, 264, 272, 280, 296, 300, 308, 316, 332, 340, 356, 372, 404, 408, 416, 424, 440, 448, 464, 480, 512, 520, 536
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(n+1)-a(n) = A001316(n)
a(0)=0, a(2n) = 2a(n-1) + a(n) + 2, a(2n+1) = 3a(n) + 2. G.f. 1/(1-x) * prod(k>=0, 1 + 2x^2^k). - Ralf Stephan (ralf(AT)ark.in-berlin.de), Oct 07 2003
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PROGRAM
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(PARI) a(n)=sum(i=1, n, 2^sum(k=1, length(binary(i)), component(binary(i), k)))
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CROSSREFS
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a(n) = A006046(n+1)-1. Cf. A080263.
Sequence in context: A034822 A050567 A069879 this_sequence A024895 A087915 A088967
Adjacent sequences: A074327 A074328 A074329 this_sequence A074331 A074332 A074333
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KEYWORD
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easy,nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 06 2002
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