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 1-8 of 8 results.

A319231 Decimal expansion of Sum_{p = prime} 1/(p*log(p)^2).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Sep 14 2018

Keywords

Comments

Computed by expanding the formalism of arXiv:0811.4739 to double integrals over the Riemann zeta function.

Examples

			1/(2*A253191) + 1/(3*A175478) +1/(5*2.59029...) +1/(7*3.7865)+ ... = 1.52097043...
		

Crossrefs

Programs

  • Mathematica
    digits = 105; precision = digits + 10;
    tmax = 500; (* integrand considered negligible beyond tmax *)
    kmax = 500; (* f(k) considered negligible beyond kmax *)
    InLogZeta[k_] := NIntegrate[(t - k) Log[Zeta[t]], {t, k, tmax}, WorkingPrecision -> precision, MaxRecursion -> 20, AccuracyGoal -> precision];
    f[k_] := With[{mu = MoebiusMu[k]}, If[mu == 0, 0, (mu/k^3)*InLogZeta[k]]];
    s = 0;
    Do[s = s + f[k]; Print[k, " ", s], {k, 1, kmax}];
    RealDigits[s][[1]][[1 ;; digits]] (* Jean-François Alcover, Jun 21 2022, after Vaclav Kotesovec *)
  • PARI
    default(realprecision, 200); s=0; for(k=1, 500, s=s+moebius(k)/k^3 * intnum(x=k,[[1], 1],(x-k)*log(zeta(x))); print(s)); \\ Vaclav Kotesovec, Jun 12 2022

Extensions

More digits from Vaclav Kotesovec, Jun 12 2022

A145419 Decimal expansion of Sum_{k>=2} 1/(k*(log k)^3).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Feb 08 2009

Keywords

Comments

Cubic analog of A115563. Evaluated by direct summation of the first 160 terms and accumulating the remainder with the 5 nontrivial terms in the Euler-Maclaurin expansion.
Theorem: Bertrand series Sum_{n>=2} 1/(n*log(n)^q) is convergent iff q > 1 (for q = 2, 4, 5 see respectively A115563, A145420, A145421). - Bernard Schott, Oct 23 2021

Examples

			2.0658865388841352509031422416437738180869752069383...
		

Crossrefs

Programs

  • Mathematica
    digits = 50; NSum[ 1/(n*Log[n]^3), {n, 2, Infinity}, NSumTerms -> 10000, WorkingPrecision -> digits + 10] // RealDigits[#, 10, digits] & // First (* Jean-François Alcover, Feb 11 2013 *)
    alfa = 3; maxiter = 20; nn = 10000; bas = Sum[1/(k*Log[k]^alfa), {k, 2, nn}] + 1/((alfa - 1)*Log[nn + 1/2]^(alfa - 1)); sub = 0; Do[sub = sub + 1/4^s/(2*s + 1)! * NSum[(D[1/(x*Log[x]^alfa), {x, 2 s}]) /. x -> k, {k, nn + 1, Infinity}, WorkingPrecision -> 120, NSumTerms -> 100000, PrecisionGoal -> 120, Method -> {"NIntegrate", "MaxRecursion" -> 100}]; Print[bas - sub], {s, 1, maxiter}] (* Vaclav Kotesovec, Jun 11 2022 *)

Extensions

More terms from Jean-François Alcover, Feb 11 2013
More digits from Vaclav Kotesovec, Jun 11 2022

A363368 Decimal expansion of Sum_{primes p} 1/(p*log(p)*log(log(p))).

Original entry on oeis.org

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

Views

Author

Artur Jasinski, Jun 11 2023

Keywords

Comments

Value computed and communicated by Bill Allombert and confirmed by Pascal Sebah.

Examples

			1.9069738480349544...
		

Crossrefs

Programs

  • PARI
    /* author Bill Allombert */
    \p150
    pz(x, ex=0)=
    {
    my(s=bitprecision(x));
    my(B=s/real(polcoef(x, 0))+ex);
    sum(n=1, B, my(a=moebius(n)); if(a!=0, a*log(zeta(n*x))/n));
    }
    my(P=primes([2, 61])); intnum(x=1, [oo, log(67)], (pz(x)-vecsum([p^-x|p<-P]))*intnum(s=0, [oo, 1], (x-1)^s/gamma(1+s))) + vecsum([1/p/log(p)/log(log(p))|p<-P])

A361089 a(n) = smallest integer x such that Sum_{k = 2..x} 1/(k*log(log(k))) > n.

Original entry on oeis.org

3, 5, 8, 21, 76, 389, 2679, 23969, 269777, 3717613, 61326301, 1188642478, 26651213526, 682263659097, 19720607003199, 637490095320530, 22857266906194526, 902495758030572213, 38993221443197045348, 1833273720522384358862
Offset: 2

Views

Author

Artur Jasinski, Jun 11 2023

Keywords

Comments

Because lim_{x->oo} (Sum_{k=2..x} 1 / (k*log(log(k)))) - li(log(x)) = 2.7977647035208... (see A363078) then a(n) = round(w) where w is the solution of the equation li(log(w)) + 2.7977647035208... = n.

Examples

			a(2) = 3 because Sum_{k=2..3} 1/(k*log(log(k))) = 2.18008755... > 2 and Sum_{k=2..2} 1/(k*log(log(k))) = -1.364208386450... < 2.
a(7) = 389 because Sum_{k=2..389} 1/(k*log(log(k))) = 7.000345... > 7 and Sum_{k=2..388} 1/(k*log(log(k))) = 6.99890560988... < 7.
		

Crossrefs

Programs

  • Mathematica
    (*slow procedure*)
    lim = 2; sum = 0; aa = {}; Do[sum = sum + N[1/(k Log[Log[k]]), 100];
     If[sum >= lim, AppendTo[aa, k]; Print[{lim, sum, k}];
      lim = lim + 1], {k, 2, 269777}];aa
    (*quick procedure *)
    aa = {3}; cons = 2.79776470352080492766050456553352884330850083202326989577856315;
    Do[ww = w /. NSolve[LogIntegral[Log[w]] + cons == n, w];
     AppendTo[aa, Round[ww][[1]]], {n, 3, 21}]; aa

Formula

For n >= 3, a(n) = round(w) where w is the solution of the equation li(log(w)) + 2.7977647035208... = n.

A363078 Decimal expansion of lim_{x->oo} (Sum_{k=2..x} 1 / (k*log(log(k)))) - li(log(x)).

Original entry on oeis.org

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

Views

Author

Artur Jasinski, Jun 11 2023

Keywords

Comments

Value computed and communicated by Pascal Sebah.
For the smallest integer x such that Sum_{k = 2..x} 1/(k*log(log(k))) > n see A361089.

Examples

			2.7977647035208...
		

Crossrefs

A354953 Decimal expansion of Sum_{p = primes} 1 / (p * log(p)^5).

Original entry on oeis.org

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

Views

Author

Vaclav Kotesovec, Jun 13 2022

Keywords

Examples

			3.359898760127253088364274368063313570407472689603469004194863140645872...
		

Crossrefs

Programs

  • Mathematica
    digits = 105; precision = digits + 15;
    tmax = 400; (* integrand considered negligible beyond tmax *)
    kmax = 400; (* f(k) considered negligible beyond kmax *)
    InLogZeta[k_] := NIntegrate[(t-k)^4 Log[Zeta[t]], {t, k, tmax},
      WorkingPrecision -> precision, MaxRecursion -> 20,
      AccuracyGoal -> precision];
    f[k_] := With[{mu = MoebiusMu[k]}, If[mu==0, 0, (mu/(4! k^6))* InLogZeta[k]]];
    s = 0; Do[s = s + f[k]; Print[k, " ", s], {k, 1, kmax}];
    RealDigits[s][[1]][[1 ;; digits]] (* Jean-François Alcover, Jun 23 2022 *)
  • PARI
    default(realprecision, 200); s=0; for(k=1, 500, s = s + moebius(k)/(4!*k^6) * intnum(x=k,[[1], 1], (x-k)^4 * log(zeta(x))); print(s));

Extensions

Last 5 digits corrected by Vaclav Kotesovec, Jun 22 2022, following a suggestion from Jean-François Alcover

A354954 Decimal expansion of Sum_{p = primes} 1 / (p * log(p)^4).

Original entry on oeis.org

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

Views

Author

Vaclav Kotesovec, Jun 13 2022

Keywords

Examples

			2.443227043544410188729683297369734576461453087740400428664651485267350...
		

Crossrefs

Programs

  • PARI
    default(realprecision, 200); s=0; for(k=1, 500, s = s + moebius(k)/(6*k^5) * intnum(x=k,[[1], 1], (x-k)^3 * log(zeta(x))); print(s));

Extensions

Last 2 digits corrected by Vaclav Kotesovec, Jun 22 2022

A366249 Decimal expansion of lim_{x->oo} (Sum_{primes p<=x} 1/(p*log(log(p)))) - log(log(log(x))).

Original entry on oeis.org

2, 9, 3, 8, 3, 2, 9, 0, 1
Offset: 1

Views

Author

Artur Jasinski, Oct 05 2023

Keywords

Comments

Value computed and communicated by Pascal Sebah.

Examples

			2.93832901...
		

Crossrefs

Showing 1-8 of 8 results.