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 A271716 Sum of numbers of divisors of positive numbers differing from n in one bit. 1
 0, 2, 3, 6, 6, 7, 8, 13, 9, 12, 13, 13, 15, 18, 10, 22, 15, 17, 16, 22, 14, 26, 14, 22, 19, 30, 13, 30, 17, 20, 20, 35, 18, 30, 20, 27, 27, 33, 18, 34, 27, 26, 20, 45, 16, 28, 26, 34, 26, 36, 21, 47, 21, 28, 26, 46, 20, 32, 24, 32, 32, 42, 16, 52, 23, 33 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For all the positive numbers m obtained from n by flipping one bit of the binary representation of n, add the number of divisors A000005(m) of m. Number of ordered pairs (a,b) of positive numbers such that a*b differs from n in exactly one binary digit, with no more binary digits than n. LINKS Robert Israel, Table of n, a(n) for n = 1..10000 EXAMPLE For n = 5, flipping one bit yields (4, 7, 1), so a(5) = A000005(4) + A000005(7) + A000005(1) = 3 + 2 + 1 = 6. MAPLE f:= proc(x)   local m;   add(numtheory:-tau(m), m=[seq(Bits:-Xor(x, 2^j), j=0..ilog2(x))]) end proc: map(f, [\$1..100]); CROSSREFS Cf. A000005. Sequence in context: A193896 A099162 A187327 * A220178 A023832 A080235 Adjacent sequences:  A271713 A271714 A271715 * A271717 A271718 A271719 KEYWORD nonn AUTHOR Robert Israel, Apr 12 2016 STATUS approved

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Last modified November 30 13:12 EST 2021. Contains 349419 sequences. (Running on oeis4.)