cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A384455 Decimal expansion of Sum_{k>=2} (-1)^k*P(k)/(k+1) - M/2 (negated), where P(s) is the prime zeta function and M is Mertens's constant.

Original entry on oeis.org

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

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Author

Amiram Eldar, May 30 2025

Keywords

Comments

The constant C in Theorem 2.2 in Jakimczuk (2025): Product_{p prime <= x} (1 + 1/p)^p = exp(PrimePi(x) + C)/sqrt(log(x)) + O(exp(PrimePi(x))/(sqrt(log(x))*exp(a*sqrt(log(x))))), where a is a positive constant, and Product_{k=1..n} (1 + 1/prime(k))^prime(k) = (exp(n + C)/sqrt(log(n))) * (1 - log(log(n))/(2*log(n)) + o(log(log(n))/log(n))).

Examples

			-0.01253463419149670110397060725717716746329257223331...
		

Crossrefs

Cf. A000720 (PrimePi), A001620, A077761 (Mertens's constant), A110544 (analogous with product over positive integers), A229495.

Programs

  • PARI
    suminf(k = 2, (1/(2*k) + (-1)^k/(k+1)) * sumeulerrat(1/p^k)) - Euler/2

Formula

Equals -gamma/2 + Sum_{k>=2} (1/(2*k) + (-1)^k/(k+1)) * P(k), where P(s) is the prime zeta function and gamma is Euler's constant (A001620).