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

A157292 Decimal expansion of 315/(2*Pi^4).

Original entry on oeis.org

1, 6, 1, 6, 8, 9, 2, 2, 0, 5, 1, 1, 2, 7, 8, 2, 7, 9, 2, 2, 9, 1, 5, 6, 3, 3, 6, 4, 5, 7, 1, 1, 9, 4, 3, 2, 7, 3, 3, 7, 8, 7, 8, 7, 9, 1, 9, 4, 8, 0, 2, 6, 3, 7, 8, 1, 1, 1, 4, 6, 5, 5, 8, 6, 8, 3, 5, 8, 5, 1, 8, 7, 1, 3, 9, 9, 4, 2, 7, 4, 3, 9, 2, 2, 8, 9, 0, 0, 1, 5, 3, 9, 0, 0, 8, 2, 5, 2, 2, 6, 3, 6, 2, 7, 2
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 5-free numbers (numbers that are not divisible by a 5th power other than 1) (Jakimczuk and Lalín, 2022). - Amiram Eldar, May 12 2023

Examples

			1.61689220511... = (1+1/2^2+1/2^4)*(1+1/3^2+1/3^4)*(1+1/5^2+1/5^4)*(1+1/7^2+1/7^4)*...
		

Crossrefs

Programs

Formula

Equals Product_{p = primes} (1 + 1/p^2 + 1/p^4), whereas, the product over (1 + 2/p^2 + 1/p^4) equals A082020^2.
Equals A013661/A013664 = Product_{i>=1} (1+1/A001248(i)+1/A030514(i)).
Equals 315*A092744/2.
Equals Sum_{n>=1} 1/A004709(n)^2. - Geoffrey Critzer, Feb 16 2015

A179706 Decimal expansion of e^(1/Pi).

Original entry on oeis.org

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

Views

Author

Bronte Harkaitz (bronteharkaitz(AT)yahoo.com), Jul 25 2010

Keywords

Examples

			e^(1/Pi) = 1.37480222743935863178...
1.3748022274... = 1 + A049541 + A092742/2! + A092743/3! + A092744/4! + A092745/5! + ... - _R. J. Mathar_, Jul 28 2010
		

Crossrefs

Cf. A001113 (decimal expansion of e, Euler's number), A000796 (decimal expansion of Pi).

Programs

Formula

log(this number) = A049541. - R. J. Mathar, Jul 28 2010

Extensions

Edited and extended by Klaus Brockhaus, Jul 29 2010
More digits from R. J. Mathar, Jul 28 2010
Showing 1-3 of 3 results.