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 A191613 Number of even divisors of lambda(n). 3
 0, 0, 1, 1, 2, 1, 2, 1, 2, 2, 2, 1, 4, 2, 2, 2, 4, 2, 3, 2, 2, 2, 2, 1, 4, 4, 3, 2, 4, 2, 4, 3, 2, 4, 4, 2, 6, 3, 4, 2, 6, 2, 4, 2, 4, 2, 2, 2, 4, 4, 4, 4, 4, 3, 4, 2, 3, 4, 2, 2, 8, 4, 2, 4, 4, 2, 4, 4, 2, 4, 4, 2, 9, 6, 4, 3, 4, 4, 4, 2, 4, 6, 2, 2, 4, 4, 4, 2, 6, 4, 4, 2, 4, 2, 6, 3, 10, 4, 4, 4, 6, 4, 4, 4, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS Lambda is the function in A002322. LINKS Antti Karttunen, Table of n, a(n) for n = 1..16384 FORMULA a(n) = A183063(A002322(n)). - Michel Marcus, Mar 18 2016 EXAMPLE a(13) = 4 because lambda(13) = 12 and the 4 even divisors are { 2, 4, 6, 12}. MATHEMATICA f[n_] := Block[{d = Divisors[CarmichaelLambda[n]]}, Count[EvenQ[d], True]]; Table[f[n], {n, 80}] (* Second program: *) Array[DivisorSum[CarmichaelLambda@ #, 1 &, EvenQ] &, 105] (* Michael De Vlieger, Dec 04 2017 *) PROG (PARI) a(n) = sumdiv(lcm(znstar(n)[2]), d, 1-(d%2)); \\ Michel Marcus, Mar 18 2016 CROSSREFS Cf. A002322, A183063, A193322, A193386. Sequence in context: A324888 A249145 A048684 * A298642 A243404 A219181 Adjacent sequences:  A191610 A191611 A191612 * A191614 A191615 A191616 KEYWORD nonn AUTHOR Michel Lagneau, Jul 22 2011 EXTENSIONS More terms from Antti Karttunen, Dec 04 2017 STATUS approved

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Last modified May 31 16:29 EDT 2020. Contains 334748 sequences. (Running on oeis4.)