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 A213595 A048784(n) / 2^A213594(n). 0
 1, 1, 3, 1, 9, 3, 1, 3, 3, 3, 1, 3, 3, 3, 15, 3, 3, 9, 3, 9, 1, 1, 15, 27, 9, 3, 15, 1, 5, 5, 3, 9, 9, 9, 3, 3, 1, 3, 45, 9, 15, 1, 15, 15, 15, 45, 9, 81, 9, 5, 5, 1, 25, 5, 3, 3, 5, 5, 3, 15, 27, 9, 21, 3, 81, 9, 3, 15, 1, 3, 75, 81, 9, 9, 135, 27, 25, 15 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS a(n) = tau(binomial(2*n,n)) / 2^k, where tau = number of divisors (A000005) and k is the greatest possible integer. LINKS Table of n, a(n) for n=1..78. EXAMPLE a(7) = 1 because A048784(7) / 2^5 = 32 / 32 = 1 is integer. MAPLE with(numtheory): for n from 1 to 100 do:ii:=0:for k from 500 by -1 to 1 while(ii=0) do: x:=evalf(tau(binomial(2*n, n))/2^k):if x=floor(x) then ii:=1: printf(`%d, `, floor(x)):else fi:od:od: CROSSREFS Cf. A048784, A213594. Sequence in context: A223140 A021762 A019736 * A140303 A249266 A309057 Adjacent sequences: A213592 A213593 A213594 * A213596 A213597 A213598 KEYWORD nonn AUTHOR Michel Lagneau, Jun 15 2012 STATUS approved

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Last modified May 29 11:01 EDT 2023. Contains 363029 sequences. (Running on oeis4.)