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 1-5 of 5 results.

A065965 Numbers k that divide A039916(k).

Original entry on oeis.org

1, 2, 3, 9, 18, 21, 43, 59, 74, 557, 8292, 31898, 68595, 530152, 599960, 724192, 1373197, 1452846, 5125588, 5776688
Offset: 1

Views

Author

Jason Earls, Dec 08 2001

Keywords

Comments

Next term, if it exists, is greater than 10000000. - Vaclav Kotesovec, Oct 06 2014

Examples

			A039916(9) = 141592653 = 9*15732517, so 9 is a term of this sequence.

Crossrefs

Cf. A039916.

Programs

  • Maple
    for n from 1 do
    if modp(A039916(n),n) = 0 then
        print(n);
    end if;
end do: # R. J. Mathar, Oct 04 2014
  • Mathematica
    picif=RealDigits[Pi-3,10,100000][[1]]; t=0; Do[t=10*t+picif[[j]]; If[Divisible[t,j],Print[j]],{j,1,Length[picif]}] (* Vaclav Kotesovec, Oct 06 2014 , 7 CPU hours with 10000000 *)
  • PARI
    a065965(m,n) = {local(pr,pi,k); pr=default(realprecision,1); default(realprecision,n); p=Pi-3; for(k=m,n, if(truncate(p*10^k)%k==0,print1(k,","))); default(realprecision,pr); }
a065965(1,2^15)

Extensions

a(12) from Klaus Brockhaus, Dec 10 2001
a(13)-a(16) from Jeff Heleen, Sep 28 2014
a(17)-a(20) from Vaclav Kotesovec, Oct 06 2014

A322776 Scan first k digits of Pi after decimal point, for k = 1,2,3,..., record all distinct numbers in the order in which they appear.

Original entry on oeis.org

1, 14, 4, 141, 41, 1415, 415, 15, 5, 14159, 4159, 159, 59, 9, 141592, 41592, 1592, 592, 92, 2, 1415926, 415926, 15926, 5926, 926, 26, 6, 14159265, 4159265, 159265, 59265, 9265, 265, 65, 141592653, 41592653, 1592653, 592653, 92653, 2653, 653, 53, 3, 1415926535
Offset: 1

Views

Author

N. J. A. Sloane, Jan 03 2019

Keywords

Comments

Skip any "numbers" that begin with 0, except 0 itself.
Presumably this is a permutation of the nonnegative numbers.
All the terms of A039916 appear in order in this sequence. - Rémy Sigrist, Jan 03 2019

Links

Crossrefs

Inspired by A323036.
Cf. A039916, A322777, A154883.

Programs

  • PARI
    pid=Pi-3; s=Set(); for (k=1, 9, pid*=10; my (f=floor(pid)); forstep (w=k, 1, -1, v=f % (10^w); if (!setsearch(s, v), print1 (v ",
"); s=setunion(s,Set(v))))) \\ Rémy Sigrist, Jan 03 2019

Extensions

More terms from Rémy Sigrist, Jan 03 2019

A039920 Concatenation of the first n decimal digits of e-2.

Original entry on oeis.org

7, 71, 718, 7182, 71828, 718281, 7182818, 71828182, 718281828, 7182818284, 71828182845, 718281828459, 7182818284590, 71828182845904, 718281828459045, 7182818284590452, 71828182845904523, 718281828459045235, 7182818284590452353, 71828182845904523536
Offset: 1

Views

Author

Felice Russo

Keywords

Crossrefs

Cf. A001113, A039916.

Programs

  • Mathematica
    Module[{nn=20,c},c=Rest[RealDigits[E,10,nn][[1]]];Table[FromDigits[ Take[ c,n]],{n,nn-1}]] (* Harvey P. Dale, Jun 08 2015 *)

Extensions

More terms from Sean A. Irvine, Feb 28 2021

A254898 Read the first n decimal digits of Pi-3 backwards.

Original entry on oeis.org

1, 41, 141, 5141, 95141, 295141, 6295141, 56295141, 356295141, 5356295141, 85356295141, 985356295141, 7985356295141, 97985356295141, 397985356295141, 2397985356295141, 32397985356295141, 832397985356295141, 4832397985356295141, 64832397985356295141, 264832397985356295141
Offset: 1

Views

Author

Christian Perfect, Feb 10 2015

Keywords

Comments

a(n) is A039916(n) read backwards.
With the 3 on the end: A092845.

Crossrefs

Cf. A000796, A004086, A039916, A092845.

Programs

  • Mathematica
    Module[{nn=30,pd},pd=Rest[RealDigits[Pi,10,nn][[1]]];Table[FromDigits[ Reverse[ Take[pd,n]]],{n,nn-1}]] (* Harvey P. Dale, Feb 07 2019 *)

Formula

a(n) = A004086(A039916(n)). - Alois P. Heinz, Feb 16 2015

A330084 a(n) is the smallest k > 0 such that n occurs immediately after the decimal point in the decimal expansion of k*Pi.

Original entry on oeis.org

36, 1, 2, 24, 3, 4, 12, 5, 6, 7, 29, 22, 15, 8, 1, 100, 93, 86, 79, 72, 65, 58, 51, 37, 30, 23, 16, 9, 2, 108, 94, 87, 80, 73, 66, 59, 52, 45, 31, 24, 17, 10, 3, 109, 102, 95, 81, 74, 67, 60, 53, 46, 39, 25, 18, 11, 4, 110, 103, 96, 89, 75, 68, 61, 54, 47, 40
Offset: 0

Views

Author

Felix Fröhlich, Dec 01 2019

Keywords

Comments

Any number occurring in this sequence occurs infinitely many times since the smallest such k for a specific n is also the smallest such k for all numbers formed by the concatenation of the initial digits after the decimal point in the decimal expansion of k*Pi.
From A266242, only 36 appears in this sequence. - Rémy Sigrist, Dec 01 2019

Examples

			For n = 0: The decimal expansion of 36*Pi starts 113.097335529232... and this is the smallest multiple of Pi where 0 occurs immediately after the decimal point, so a(0) = 36.

Crossrefs

Cf. A000796, A039916, A266242.

Programs

  • Mathematica
    a[n_]:=(k=1;While[Floor[(Pi*k-Floor[Pi*k])*10^Length[IntegerDigits[n]]]!=n,k++];Return[k]);Table[a[n],{n,0,67}] (* Joshua Oliver, Dec 01 2019 *)
  • PARI
    pidigits(multipl, len) = floor((Pi*multipl - floor(Pi*multipl)) * 10^len)
a(n) = for(k=1, oo, if(pidigits(k, #Str(n))==n, return(k)))

Formula

a(n) = 1 iff n belongs to A039916. - Rémy Sigrist, Dec 01 2019
Showing 1-5 of 5 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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