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.

Showing 1-3 of 3 results.

A092742 Decimal expansion of 1/Pi^2.

Original entry on oeis.org

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

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Author

Mohammad K. Azarian, Apr 12 2004

Keywords

Comments

The asymptotic density of squarefree numbers that are divisible by 5. - Amiram Eldar, Mar 25 2021

Examples

			0.101321183642337771443879463209727638904358774672246548845609...
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 3.6.1, p. 220.

Crossrefs

Cf. A000796 (Pi), A002388 (Pi^2), A091925 (Pi^3), A092425 (Pi^4), A092731 (Pi^5), A092732 (Pi^6), A092735 (Pi^7), A092736 (Pi^8).
Cf. A049541 (1/Pi), A092743 (1/Pi^3), A092744 (1/Pi^4), A092745 (1/Pi^5), A092746 (1/Pi^6), A092747 (1/Pi^7), A092748 (1/Pi^8).

Programs

A157294 Decimal expansion of 1575/Pi^6.

Original entry on oeis.org

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

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Author

R. J. Mathar, Feb 26 2009

Keywords

Comments

Equals the asymptotic mean of the abundancy index of the 7-free numbers (numbers that are not divisible by a 7th power other than 1) (Jakimczuk and Lalín, 2022). - Amiram Eldar, May 12 2023

Examples

			1.63825432044096736634149427498... = (1+1/2^2+1/2^4+1/2^6)*(1+1/3^2+1/3^4+1/3^6)*(1+1/5^2+1/5^4+1/5^6)*(1+1/7^2+1/7^4+1/7^6)*...
		

Crossrefs

Programs

Formula

Equals Product_{p = primes = A000040} (1+1/p^2+1/p^4+1/p^6).
Equals A013661/A013666 = A082020*A157290 = Product_{i>=1} (1+1/A001248(i)+1/A030514(i)+1/A030516(i)) = 1575*A092746.

A157295 Decimal expansion of 630/Pi^6.

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Feb 26 2009

Keywords

Examples

			0.655301728176386946536... = (1-1/2^2+1/2^4-1/2^6)*(1-1/3^2+1/3^4-1/3^6)*(1-1/5^2+1/5^4-1/5^6)*(1-1/7^2+1/7^4-1/7^6)*...
		

Crossrefs

Programs

  • Maple
    evalf(630/Pi^6) ;
  • Mathematica
    RealDigits[630/Pi^6, 10, 120][[1]] (* Amiram Eldar, Jun 10 2023 *)
  • PARI
    630/Pi^6 \\ Michel Marcus, Aug 05 2021

Formula

Equals Product_{p primes = A000040} (1-1/p^2+1/p^4-1/p^6).
Equals Product_{i>=1} (1-1/A001248(i)+1/A030514(i)-1/A030516(i)).
Equals 630*A092746.
Equals Sum_{n>=1} A363551(n)/n^2. - Amiram Eldar, Jun 10 2023
Showing 1-3 of 3 results.