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 A277892 a(n) = A001222(A048675(n)). 11
 0, 1, 1, 2, 1, 3, 1, 2, 1, 4, 2, 5, 2, 2, 2, 6, 1, 7, 2, 2, 1, 8, 1, 3, 2, 2, 2, 9, 1, 10, 1, 3, 2, 3, 2, 11, 2, 2, 1, 12, 1, 13, 3, 3, 1, 14, 2, 4, 2, 3, 2, 15, 1, 3, 1, 3, 4, 16, 3, 17, 3, 3, 2, 4, 1, 18, 3, 3, 1, 19, 1, 20, 2, 2, 3, 4, 2, 21, 3, 3, 2, 22, 3, 3, 2, 2, 1, 23, 2, 4, 3, 5, 3, 4, 1, 24, 1, 3, 2, 25, 1, 26, 2, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,4 COMMENTS For n >= 3, a(n) = index of the row where n is located in array A277898. LINKS Antti Karttunen (terms 2..3465) and Hans Havermann, Table of n, a(n) for n = 2..10000 FORMULA a(n) = A001222(A048675(n)). a(A019565(n)) = a(A260443(n)) = A001222(n). For all n >= 2, a(A065091(n)) = n. PROG (Scheme) (define (A277892 n) (if (= 1 n) 0 (A001222 (A048675 n)))) (PARI) A048675(n) = my(f = factor(n)); sum(k=1, #f~, f[k, 2]*2^primepi(f[k, 1]))/2; A277892(n) = if(1==n, 0, bigomega(A048675(n))); for(n=1, 3465, write("b277892.txt", n, " ", A277892(n))); (Python) from sympy import factorint, primepi, primefactors def a001222(n): return 0 if n==1 else a001222(n//primefactors(n)[0]) + 1 def a048675(n):     if n==1: return 0     f=factorint(n)     return sum(f[i]*2**(primepi(i) - 1) for i in f) def a(n): return a001222(a048675(n)) print([a(n) for n in range(2, 101)]) # Indranil Ghosh, Jun 19 2017 CROSSREFS Left inverse of A065091. Cf. A001222, A048675. Cf. A277319 (positions of ones). Cf. A000040 (positions of records), A277900. Cf. A277895 (ordinal transform from a(3) onward). Cf. A277893, A277894, A277898. Sequence in context: A325565 A286552 A324826 * A214743 A331179 A026100 Adjacent sequences:  A277889 A277890 A277891 * A277893 A277894 A277895 KEYWORD nonn AUTHOR Antti Karttunen, Nov 08 2016 STATUS approved

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Last modified June 15 12:29 EDT 2021. Contains 345048 sequences. (Running on oeis4.)