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A374213
The 3-adic valuation of A328768(n), where A328768 is the first primorial based variant of the arithmetic derivative.
7
0, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 3, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 3, 2, 4, 0, 0, 1, 0, 1, 0, 1, 1, 2, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 2, 0, 1, 0, 3, 0, 1, 0, 1, 0, 0, 1, 1, 1, 2, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 4
OFFSET
2,26
LINKS
FORMULA
a(n) = A007949(A328768(n)).
PROG
(PARI)
A002110(n) = prod(i=1, n, prime(i));
A328768(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]*A002110(primepi(f[i, 1])-1)/f[i, 1]));
A374213(n) = valuation(A328768(n), 3);
CROSSREFS
Cf. A007949, A328768, A373991, A373992 (after its two initial terms, gives the indices of nonzero terms in this sequence).
Cf. also A374133, A374212.
Sequence in context: A317946 A347439 A347048 * A140807 A232629 A340007
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 30 2024
STATUS
approved