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A368916
a(n) = 1 if there is no prime p such that p^p divides the arithmetic derivative of A276086(n), and 0 otherwise, where A276086 is the primorial base exp-function.
10
0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1
OFFSET
0
COMMENTS
Question: What is the asymptotic mean of this sequence (equal to the density of A368914 or A368915 when restricted to the terms of A048103)? Straightness of the graphs of A368917, A368918 and A368906 seems to indicate that the expected value of A368914(n) is not correlated with the specific features (like the magnitude of its exponents) in the prime factorization of n.
Answer: If the conjecture that "For any given prime p, the distribution of the p-adic valuations of n' among those n that are not multiples of p, is the same as the distribution of the p-adic valuations among all the natural numbers", then the asymptotic mean of this sequence is equal to Product_{p prime} (1 - 1/p^(1+p)) = 0.864142072322... See also A368919, A360111 and A369653. - Antti Karttunen, Jan 29 and Feb 10 2024
FORMULA
a(n) = A368914(A276086(n)) = A368915(A276086(n)).
a(n) = A359550(A327860(n)) = A359550(A342002(n)).
a(n) = 1 - A360111(A276086(n)).
a(n) = [0 == A342019(n)], where [ ] is the Iverson bracket.
For n > 0, a(n) >= A328306(n).
PROG
(PARI)
A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A359550(n) = { my(f = factor(n)); prod(k=1, #f~, (f[k, 2]<f[k, 1])); };
A368916(n) = { my(u=A276086(n)); ((u>1)&&A359550(A003415(u))); };
CROSSREFS
Characteristic function of A368917 whose complement A342018 gives the positions of zeros after the initial one at a(0).
Sequence in context: A374128 A304438 A168181 * A324732 A164980 A252372
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 09 2024
STATUS
approved