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.

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A354952 Decimal expansion of Sum_{p primes} 1/(p*log(p) - 1).

Original entry on oeis.org

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

Views

Author

Vaclav Kotesovec, Jun 13 2022

Keywords

Examples

			3.663504585465603301602825244808212333209344522564373994...
		

Crossrefs

Programs

  • PARI
    prec = 60; tot = 0; dif = 10^(-prec); for(s=1, 200, default(realprecision, 200 + 6*s); su = 0; d = 0; k = 0; while(abs(d)>dif || exponent(d)==-oo, k=k+1; d = moebius(k) / ((s-1)! * k^(s+1)) * intnum(x=s*k, [[1], 1], (x-s*k)^(s-1) * log(zeta(x))); su = su + d; ); tot = tot + su; print(tot);); \\ It takes several hours.

Formula

Equals Sum_{k>=1} (Sum_{p primes} 1/(p*log(p))^k).

A370112 Decimal expansion of Lichtman constant f(N*(3)).

Original entry on oeis.org

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

Views

Author

Artur Jasinski, Feb 10 2024

Keywords

Comments

For definition and links see A370093.

Examples

			0.71312380050989...
		

Crossrefs

A370113 Decimal expansion of Lichtman constant f(N*(4)).

Original entry on oeis.org

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

Views

Author

Artur Jasinski, Feb 10 2024

Keywords

Comments

For definition and links see A370093.

Examples

			0.6528129098554...
		

Crossrefs

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])

A372765 Decimal expansion of Lichtman constant f(N(2)).

Original entry on oeis.org

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

Views

Author

Artur Jasinski, May 14 2024

Keywords

Comments

Definition:
f(N(k)) = Sum_{n>1 and (big) Omega(n)=k} 1/(n*log(n)), where (big) Omega is number of prime divisors of n counted with multiplicity see A001222.
f(N(k)) = Integral_{s>=1} P_k(s), where P_k(s) = Sum_{n>1 and (big) Omega(n)=k} 1/n^s.
Lichtman constant f(N(1)) see A137245.
Lichtman constant f(N(2)) this sequence.
Lichtman constant f(N(3)) see A372827.
Lichtman constant f(N(4)) see A372828.
Minimal value of f(N(k)) occurs for k=6 f(N(6)) = 0.9887534530145...
For k>=6, 1 > f(N(k+1)) > f(N(k)).
When k -> oo then f(N(k)) -> 1.
Value computed and communicated by Bill Allombert.

Examples

			1.1448165734059179915...
		

Crossrefs

Programs

  • PARI
    pz(x)= sum(n=1, max(2, bitprecision(x)/x), my(a=moebius(n)); if(a!=0, a*log(zeta(n*x))/n));
    Lichtman(n)=intnum(s=1, [oo, log(2)], exp(sum(i=1, n, pz(i*s)*x^i/i)+O(x^(n+1)))-1)
    Lichtman(20)
    \\ Bill Allombert, May 14 2024 [via Artur Jasinski]

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

A372827 Decimal expansion of Lichtman constant f(N(3)).

Original entry on oeis.org

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

Views

Author

Artur Jasinski, May 14 2024

Keywords

Comments

For definition and links see A372765.

Examples

			1.0308351017932175719...
		

Crossrefs

A372828 Decimal expansion of Lichtman constant f(N(4)).

Original entry on oeis.org

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

Views

Author

Artur Jasinski, May 14 2024

Keywords

Comments

For definition and links see A372765.

Examples

			0.997342148595252359...
		

Crossrefs

A137250 Decimal expansion of the constant sum 1/(q*log(q)), summed over prime powers q > 1.

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Mar 09 2008

Keywords

Comments

Evaluated from Sum_{m,k >= 1} A008683(k)*I(k*m)/k^2, where I(x) = Integral_{t=x..infinity} log zeta(t) dt is Cohen's underivative.

Examples

			2.0066664528310687...
		

References

  • Henri Cohen, Number Theory, Volume II: Analytic and Modern Tools, GTM Vol. 240, Springer, 2007; see pp. 208-209.

Crossrefs

Programs

  • PARI
    default(realprecision, 200); su = 0; for(s=1, 400, su = su + sum(k=1, 500, moebius(k)/k^2 * intnum(x=s*k,[[1], 1], log(zeta(x))))/s; print(su)); \\ Vaclav Kotesovec, Jun 12 2022

Formula

Equals Sum_{n>=2} 1/(A000961(n)*log(A000961(n))).
Equals Sum_{p primes} -log(1-1/p)/log(p). - Vaclav Kotesovec, Jun 12 2022

Extensions

8 more digits from R. J. Mathar, Dec 04 2008
More terms from Vaclav Kotesovec, Jun 12 2022
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