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.

A242624 Decimal expansion of Product_{n>1} (1-1/n)^(1/n).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, May 19 2014

Keywords

Examples

			0.4545121805146463170328014636843273993...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 2.9, pp. 121-122.

Crossrefs

Programs

  • Magma
    SetDefaultRealField(RealField(100)); L:=RiemannZeta();  Exp((&+[(Evaluate(L,n)-1)/(1-n): n in [2..10^3]])); // G. C. Greubel, Nov 15 2018
    
  • Maple
    evalf(exp(-sum((1-Zeta(n))/(1-n), n=2..infinity)), 120); # Vaclav Kotesovec, Dec 11 2015
  • Mathematica
    Exp[-NSum[(1-Zeta[n])/(1-n), {n, 2, Infinity}, NSumTerms -> 300, WorkingPrecision -> 110]] // RealDigits[#, 10, 100]& // First
  • PARI
    default(realprecision, 100); exp(suminf(n=2, (zeta(n)-1)/(1-n))) \\ G. C. Greubel, Nov 15 2018
    
  • Sage
    numerical_approx(exp(sum((zeta(k)-1)/(1-k) for k in [2..1000])), digits=100) # G. C. Greubel, Nov 15 2018

Formula

From Amiram Eldar, Feb 06 2022: (Start)
Equals exp(-A085361).
Equals 1/A245254. (End)

Extensions

Mma modified and data extended by Jean-François Alcover, May 23 2014

A244625 Decimal expansion of Product_{n>1} (1 - 1/n^2)^(1/n).

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Jul 02 2014

Keywords

Examples

			0.7993704013063328789872528539753525668777...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 2.9 Alladi-Grinstead Constant, p. 122.

Crossrefs

Programs

  • Magma
    SetDefaultRealField(RealField(100)); L:=RiemannZeta();  Exp(-(&+[(Evaluate(L, 2*n+1)-1)/n: n in [1..10^3]])); // G. C. Greubel, Nov 15 2018
    
  • Maple
    evalf(exp(-sum((Zeta(2*n+1)-1)/n, n=1..infinity)), 120); # Vaclav Kotesovec, Dec 11 2015
  • Mathematica
    digits = 102; Exp[-NSum[(Zeta[2*n+1]-1)/n, {n, 1, Infinity}, NSumTerms -> 300, WorkingPrecision -> digits+10]] // RealDigits[#, 10, digits]& // First
  • PARI
    default(realprecision, 100); exp(-suminf(n=1, (zeta(2*n+1)-1)/n)) \\ G. C. Greubel, Nov 15 2018
    
  • Sage
    numerical_approx(exp(-sum((zeta(2*n+1)-1)/n for n in [1..1000])), digits=100) # G. C. Greubel, Nov 15 2018

Formula

Equals exp(-Sum_{n>0} (zeta(2*n+1) - 1)/n).
Equals A242623 * A242624.
Also equals A242623 * exp(-A085361).

A272028 Decimal expansion of Product_{p prime} (1+1/p)^(1/p), an infinite product considered and computed by Marc Deléglise.

Original entry on oeis.org

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

Views

Author

Jean-François Alcover, Apr 18 2016

Keywords

Examples

			1.46819112232299378107910175565555486192182334313301519669833294...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge, 2003, Section 2.9 p. 122.

Crossrefs

Cf. A242623 (same product without restriction to primes).

Programs

  • Mathematica
    digits = 98; Exp[NSum[(-1)^(n-1)*PrimeZetaP[n-1]/(n-2), {n, 3, Infinity}, WorkingPrecision -> digits+10, Method -> "AlternatingSigns"]] // RealDigits[#, 10, digits]& // First
Showing 1-3 of 3 results.