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.

A345974 Decimal expansion of Sum_{k>=0} Product_{i=1..k} 1/(prime(i)-1).

Original entry on oeis.org

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

Views

Author

Hugo Pfoertner, Jun 30 2021

Keywords

Examples

			2.64810175970147102337088414536064714927258700214033932076744547925274...
		

Crossrefs

Programs

  • Maple
    c:= sum(product(1/(ithprime(i)-1), i=1..k), k=0..infinity):
    evalf(c, 140);  # Alois P. Heinz, Jun 30 2021
  • PARI
    suminf(k=0,prod(i=1,k,1/(prime(i)-1)))

Formula

Equals Sum_{k>=0} 1/A005867(k) = Sum_{k>=1} 1/A055932(k) = Sum_{k>=1} 1/A057335(k). - Amiram Eldar, Jun 26 2025