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 A006583 a(n) = Sum_{k=1..n-1} (k OR n-k). (Formerly M4069) 3
 1, 6, 8, 16, 25, 42, 44, 56, 69, 94, 108, 136, 165, 210, 208, 224, 241, 278, 296, 336, 377, 442, 460, 504, 549, 622, 668, 744, 821, 930, 912, 928, 945, 998, 1016, 1072, 1129, 1226, 1244, 1304 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 REFERENCES Marc LeBrun, personal communication. N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS M. Le Brun, Email to N. J. A. Sloane, Jul 1991 FORMULA G.f.: 1/(1-x)^2 * sum(k>=0, 2^k*t^2(4t^2+6t+1)/(1+t)^2, t=x^2^k). - Ralf Stephan, Feb 12 2003 a(0)=a(1)=0, a(2n) = 2a(n)+2a(n-1)+5n-4, a(2n+1) = 4a(n)+6n. - Ralf Stephan, Oct 09 2003 MATHEMATICA Table[Sum[BitOr[k, n-k], {k, n-1}], {n, 2, 50}] (* Harvey P. Dale, Dec 05 2020 *) PROG (PARI) a(n)=sum(k=1, n-1, bitor(k, n-k)) \\ Charles R Greathouse IV, Aug 11 2017 CROSSREFS Antidiagonal sums of array A003986. Sequence in context: A315940 A048228 A067543 * A011989 A270821 A139452 Adjacent sequences:  A006580 A006581 A006582 * A006584 A006585 A006586 KEYWORD nonn,base AUTHOR STATUS approved

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Last modified September 20 16:50 EDT 2021. Contains 347586 sequences. (Running on oeis4.)