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 A161606 a(n) = gcd(A008472(n), A001222(n)). 2
 0, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 3, 3, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 3, 1, 1, 1, 1, 1, 5, 1, 1, 2, 3, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 5, 1, 1, 1, 3, 2, 3, 1, 1, 1, 1, 1, 4, 2, 1, 2, 1, 1, 2, 2, 1, 2, 1, 2, 1, 1, 3, 1, 1, 1, 1, 1, 1, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 EXAMPLE 28 has a prime-factorization of: 2^2 * 7^1. The sum of the distinct primes dividing 28 is 2+7 = 9. The sum of the exponents in the prime-factorization of 28 is 2+1 = 3. a(28) therefore equals gcd(9,3) = 3. MAPLE A008472 := proc(n) if n = 1 then 0 ; else add(p, p= numtheory[factorset](n)) ; end if ; end proc: A161606 := proc(n) igcd(A008472(n), numtheory[bigomega](n)) ; end proc: seq(A161606(n), n=2..80) ; # R. J. Mathar, Jul 08 2011 MATHEMATICA Table[GCD[DivisorSum[n, # &, PrimeQ], PrimeOmega@ n], {n, 105}] (* Michael De Vlieger, Jul 20 2017 *) PROG (Scheme) (define (A161606 n) (gcd (A001222 n) (A008472 n))) ;; Antti Karttunen, Jul 20 2017 (Python) from sympy import primefactors, gcd def a001222(n): return 0 if n==1 else a001222(n/primefactors(n)[-1]) + 1 def a(n): return gcd(sum(primefactors(n)), a001222(n)) print map(a, range(1, 151)) # Indranil Ghosh, Jul 20 2017 CROSSREFS Cf. A001222, A008472. Sequence in context: A131789 A108465 A069347 * A300362 A248145 A171398 Adjacent sequences:  A161603 A161604 A161605 * A161607 A161608 A161609 KEYWORD nonn AUTHOR Leroy Quet, Jun 14 2009 EXTENSIONS Term a(1)=0 prepended and more terms computed by Antti Karttunen, Jul 20 2017 STATUS approved

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Last modified August 7 06:02 EDT 2020. Contains 336274 sequences. (Running on oeis4.)