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 A083015 a(n) = the number of ordered pairs of n-bit bit strings, such that both bit strings have at least n/2 one-bits, or both have at most n/2 one-bits. 0
 1, 2, 14, 32, 206, 512, 3128, 8192, 48238, 131072, 750584, 2097152, 11746424, 33554432, 184558304, 536870912, 2908113518, 8589934592, 45923227448, 137438953472, 726419131576, 2199023255552, 11506072128224, 35184372088832 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS FORMULA a(n) = 4^n/2 + 2^n*c - c^2/2; where c is (n choose n/2) for even n, 0 for odd n. EXAMPLE a(2)=14 because of the 16 ordered pairs, only (00,11) and (11,00) do not qualify. CROSSREFS Sequence in context: A231050 A337338 A322074 * A282036 A050591 A073535 Adjacent sequences:  A083012 A083013 A083014 * A083016 A083017 A083018 KEYWORD nonn AUTHOR Jon Perry, May 31 2003 EXTENSIONS Edited by Don Reble, Nov 07 2005 STATUS approved

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Last modified September 26 11:08 EDT 2021. Contains 347665 sequences. (Running on oeis4.)