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 A107473 Sum of numerator and denominator of product{p|n,p=primes} (1 -1/p). 0
 2, 3, 5, 3, 9, 4, 13, 3, 5, 7, 21, 4, 25, 10, 23, 3, 33, 4, 37, 7, 11, 16, 45, 4, 9, 19, 5, 10, 57, 19, 61, 3, 53, 25, 59, 4, 73, 28, 21, 7, 81, 9, 85, 16, 23, 34, 93, 4, 13, 7, 83, 19, 105, 4, 19, 10, 31, 43, 117, 19, 121, 46, 11, 3, 113, 43, 133, 25, 113, 47, 141, 4, 145, 55, 23, 28 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS FORMULA a(n) = A076511(n) + A076512(n). - Michel Marcus, Aug 16 2019 EXAMPLE a(12) = 4 = 1+3 because (1 -1/2)(1 -1/3) = 1/3. MAPLE a:=proc(n) local b, ct, f; with(numtheory): b:=convert(factorset(n), list): ct:=nops(b): f:=simplify(product(1-1/b[j], j=1..ct)):numer(f)+denom(f) end: seq(a(n), n=1..100); # Emeric Deutsch, May 28 2005 CROSSREFS Cf. A076511, A076512. Sequence in context: A125677 A051358 A211245 * A105574 A105562 A323704 Adjacent sequences:  A107470 A107471 A107472 * A107474 A107475 A107476 KEYWORD nonn AUTHOR Leroy Quet, May 27 2005 EXTENSIONS More terms from Emeric Deutsch, May 28 2005 STATUS approved

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Last modified January 24 13:24 EST 2020. Contains 331193 sequences. (Running on oeis4.)