A154928 - OEIS

A154928

Decimal expansion of Sum_{q in A001358} log(q)/q^2 over the semiprimes q = 4,6,9,...

0, 2, 8, 3, 6, 0, 6, 8, 1, 5, 4, 0, 7, 9, 8, 0, 6, 5, 2, 2, 2, 4, 2, 5, 8, 2, 2, 2, 5, 4, 8, 2, 7, 8, 3, 3, 6, 0, 7, 9, 3, 5, 0, 5, 7, 8, 2, 3, 7, 8, 1, 4, 0, 1, 3, 4, 1, 1, 1, 1

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OFFSET

0,2

COMMENTS

Semiprime analog of A136271. The absolute value of the first derivative of the semiprime zeta function at 2.

LINKS

Table of n, a(n) for n=0..59.

R. J. Mathar, Series of reciprocal powers of k-almost primes, arXiv:0803.0900 [math.NT], 2008-2009; see Table 4 in version 3.

FORMULA

Equals Sum_{j>=1} log(A001358(j))/A074985(j).

EXAMPLE

Equals 0.0283606815... = log(4)/16 + log(6)/36 + log(9)/81 + ....

CROSSREFS

Sequence in context: A278115 A222296 A258223 * A201394 A169844 A076123

Adjacent sequences: A154925 A154926 A154927 * A154929 A154930 A154931

KEYWORD

cons,nonn,more

AUTHOR

R. J. Mathar, Jan 17 2009

EXTENSIONS

Missing zero inserted. Artur Jasinski, Jul 29 2025

STATUS

approved