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 1-4 of 4 results.

A330594 Decimal expansion of Product_{primes p} (1 + 1/p^2 - 2/p^3).

Original entry on oeis.org

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

Views

Author

Vaclav Kotesovec, Dec 19 2019

Keywords

Examples

			1.106960111953217676651179130007439592949548833658122419043134044978777...
		

Crossrefs

Programs

  • Mathematica
    Do[Print[N[Exp[-Sum[q = Expand[(-p^2 + 2*p^3)^j]; Sum[PrimeZetaP[Exponent[q[[k]], p]] * Coefficient[q[[k]], p^Exponent[q[[k]], p]], {k, 1, Length[q]}]/j, {j, 1, t}]], 110]], {t, 20, 200, 20}]
  • PARI
    prodeulerrat(1 + 1/p^2 - 2/p^3) \\ Amiram Eldar, Mar 16 2021

A335705 Decimal expansion of Sum_{primes p} 2*(p-3) * log(p) / (p^3 + p - 2).

Original entry on oeis.org

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

Views

Author

Vaclav Kotesovec, Jun 18 2020

Keywords

Examples

			0.079339315977982136748150057589344450315501605856610561211269...
		

Crossrefs

Programs

  • Mathematica
    ratfun = 2*(p-3) / (p^3 + p - 2); zetas = 0; ratab = Table[konfun = Simplify[ratfun + c/(p^power - 1)] // Together; coefs = CoefficientList[Numerator[konfun], p]; sol = Solve[Last[coefs] == 0, c][[1]]; zetas = zetas + c*Zeta'[power]/Zeta[power] /. sol; ratfun = konfun /. sol, {power, 2, 20}]; Do[Print[N[Sum[Log[p]*ratfun /. p -> Prime[k], {k, 1, m}] + zetas, 100]], {m, 2000, 20000, 2000}]

A335706 Decimal expansion of Sum_{primes p} 2*p*(2*p^3 - 9*p^2 - 1) * log(p)^2 / (p^3 + p - 2)^2.

Original entry on oeis.org

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

Views

Author

Vaclav Kotesovec, Jun 18 2020

Keywords

Examples

			0.23510971407787662832341660852337712786303845218859602743433...
		

Crossrefs

Programs

  • Mathematica
    ratfun = 2*p*(2*p^3 - 9*p^2 - 1) / (p^3 + p - 2)^2; zetas = 0; ratab = Table[konfun = Together[Simplify[ratfun - c*(p^power/(p^power - 1)^2)]]; coefs = CoefficientList[Numerator[konfun], p]; sol = Solve[Last[coefs] == 0, c][[1]]; zetas = zetas + c*(-Zeta'[power]^2/Zeta[power]^2 + Zeta''[power]/Zeta[power]) /. sol; ratfun = konfun /. sol, {power, 2, 20}]; Do[Print[N[Sum[Log[p]^2*ratfun /. p -> Prime[k], {k, 1, m}] + zetas, 100]], {m, 2000, 20000, 2000}]

A300828 Multiplicative with a(p^2) = 1, a(p^3) = -2 and a(p^e) = 0 when e = 1 or e > 3.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, -2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, -2
Offset: 1

Views

Author

Antti Karttunen, Mar 21 2018

Keywords

Comments

Used for computing A208133.

Examples

			For n = 216 = 2^3 * 3^3, a(2^3) * a(3^3) = -2 * -2 = 4.
		

Crossrefs

Cf. A208133.

Programs

  • Mathematica
    f[p_, e_] := Switch[e, 2, 1, 3, -2, , 0]; a[n] := Times @@ f @@@ FactorInteger[n]; a[1] = 1; Array[a, 100] (* Amiram Eldar, Sep 05 2023 *)
  • PARI
    A300828(n) = { if(1==n, return(1)); my(val=1, v=factor(n), d=matsize(v)[1]); for(i=1,d, if(v[i,2] < 2 || v[i,2] > 3, return(0)); if (v[i,2] == 3, val *= -2)); return(val); }; \\ R. J. Mathar, Antti Karttunen, Mar 21 2018
    
  • Scheme
    ;; With memoization-macro definec.
    (definec (A300828 n) (if (= 1 n) n (* (case (A067029 n) ((2) 1) ((3) -2) (else 0)) (A300828 (A028234 n)))))
Showing 1-4 of 4 results.