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 1-10 of 16 results. Next

A134800 Concatenation of next n partition numbers A000041.

Original entry on oeis.org

1, 12, 357, 11152230, 425677101135, 176231297385490627, 792100212551575195824363010, 37184565560468428349101431231014883, 179772163726015311853733844583531746326175175
Offset: 1

Views

Author

Omar E. Pol, Nov 12 2007

Keywords

Crossrefs

Cf. A000041, A053067, A132926, A133013. See A134801 for another version.

Programs

  • Mathematica
    FromDigits[Flatten[IntegerDigits/@#]]&/@With[{nn=10},TakeList[ PartitionsP[ Range[0,(nn(nn+1))/2]],Range[nn]]] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Jul 25 2019 *)

Extensions

Edited by Charles R Greathouse IV, Apr 28 2010

A134801 Concatenation of next n partition numbers of positive integers.

Original entry on oeis.org

1, 23, 5711, 15223042, 5677101135176, 231297385490627792, 1002125515751958243630103718, 456556046842834910143123101488317977, 216372601531185373384458353174632617517589134
Offset: 1

Views

Author

Omar E. Pol, Nov 12 2007

Keywords

Crossrefs

Cf. A053067, A132926, A133013. Partition numbers: A000041. See A134800 for another version of the concatenation of next n partition numbers.

Programs

  • Mathematica
    Module[{nn=10},FromDigits[Flatten[IntegerDigits/@#]]&/@TakeList[ PartitionsP[ Range[ (nn(nn+1))/2]],Range[nn]]] (* Harvey P. Dale, Apr 18 2022 *)

Extensions

Edited by Charles R Greathouse IV, Apr 28 2010

A133026 Concatenation of next n Fermat numbers A000215.

Original entry on oeis.org

3, 517, 257655374294967297
Offset: 1

Views

Author

Omar E. Pol, Nov 09 2007

Keywords

Comments

a(4) has 292 digits and is too large to include.

Crossrefs

Programs

  • Mathematica
    a[n_] := FromDigits[Flatten[IntegerDigits[Table[2^(2^(k - 1)) + 1, {k, n*(n - 1)/2 + 1, n*(n + 1)/2}]]]]; Array[a, 3] (* Amiram Eldar, Jul 09 2025 *)

A133069 Successive digits of twin primes A001097.

Original entry on oeis.org

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

Views

Author

Omar E. Pol, Nov 10 2007

Keywords

Comments

Also, with offset 0, decimal expansion of the constant by concatenate twin primes. Example: 0.35711131719293141435961... Hence, subsequence of A033308. - Omar E. Pol, Oct 21 2017

Crossrefs

Programs

  • Mathematica
    Flatten[IntegerDigits/@Union[Flatten[Select[Partition[Prime[ Range[ 100]],2,1], Last[#]- First[#] == 2&]]]] (* Harvey P. Dale, May 29 2014 *)

A133074 Concatenation of next n isolated primes.

Original entry on oeis.org

2, 2337, 475367, 79838997, 113127131157163, 167173211223233251, 257263277293307317331, 337353359367373379383389, 397401409439443449457467479, 487491499503509541547557563577
Offset: 1

Views

Author

Omar E. Pol, Nov 10 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Module[{ip=Select[Prime[Range[200]],NoneTrue[#+{2,-2},PrimeQ]&],c},c = Floor[ (Sqrt[8 Length[ip]+1]-1)/2];FromDigits[Flatten[IntegerDigits/@#]]&/@TakeList[ ip,Range[c]]] (* Harvey P. Dale, Jun 09 2022 *)

A134714 Concatenation of next n Catalan numbers.

Original entry on oeis.org

1, 12, 51442, 13242914304862, 16796587862080127429002674440, 96948453535767012964479047763870017672631906564120420, 2446626702091482563640343059613650128990414732448619464014521836735307215269533550916004
Offset: 1

Views

Author

Omar E. Pol, Nov 12 2007

Keywords

Crossrefs

Cf. A053067, A053068, A133013. Catalan numbers: A000108.

Programs

  • Mathematica
    Module[{nn=50,cn},cn=CatalanNumber[Range[0,nn]];Table[ FromDigits[ Flatten[ IntegerDigits/@ Take[cn,{(n(n+1))/2+1,((n+1)(n+2))/2}]]],{n,0,Floor[ (Sqrt[ 8*nn+1]-1)/2]-1}]] (* Harvey P. Dale, May 15 2014 *)
    Module[{nn=8},FromDigits[Flatten[IntegerDigits/@#]]&/@Rest[TakeList[CatalanNumber[Range[0,(nn(nn+1))/2-1]],Range[0,nn-1]]]] (* Harvey P. Dale, Oct 06 2024 *)

Extensions

Edited by Charles R Greathouse IV, Apr 25 2010

A134723 Concatenation of next n odd primes.

Original entry on oeis.org

3, 57, 111317, 19232931, 3741434753, 596167717379, 838997101103107109, 113127131137139149151157, 163167173179181191193197199, 211223227229233239241251257263, 269271277281283293307311313317331
Offset: 1

Views

Author

Omar E. Pol, Nov 10 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Module[{nterms=12,max},max=(nterms(nterms+1))/2+1; FromDigits[ Flatten[ IntegerDigits/@#]]&/@ With[ {pr=Prime[Range[2,max]]},Table[Take[pr, {(n(n-1))/2+1,(n(n+1))/2}],{n,nterms}]]] (* Harvey P. Dale, Nov 25 2012 *)
    Module[{nn=20},FromDigits[Flatten[IntegerDigits/@#]]&/@TakeList[Prime[ Range[ 2,(nn(nn+1))/2+1]],Range[nn]]] (* Harvey P. Dale, Mar 27 2022 *)

A134733 Concatenation of next n imperfect numbers.

Original entry on oeis.org

1, 23, 457, 891011, 1213141516, 171819202122, 23242526272930, 3132333435363738, 394041424344454647, 48495051525354555657, 5859606162636465666768, 697071727374757677787980
Offset: 1

Views

Author

Omar E. Pol, Nov 12 2007

Keywords

Crossrefs

Cf. A053067, A132943, A133013. Imperfect numbers: A132999.

Programs

  • Mathematica
    Module[{nn=120,in,len},in=Select[Range[nn],DivisorSigma[1,#]!=2#&];len= Floor[x/.Last[Solve[(x(x+1))/2==Length[in]]]];FromDigits[Flatten[ IntegerDigits/@ #]]&/@TakeList[in,Range[len]]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 01 2020 *)

A134794 Concatenation of next n composite numbers.

Original entry on oeis.org

4, 68, 91012, 14151618, 2021222425, 262728303233, 34353638394042, 4445464849505152, 545556575860626364, 65666869707274757677, 7880818284858687889091
Offset: 1

Views

Author

Omar E. Pol, Nov 26 2007

Keywords

Crossrefs

Cf. A053067, A133013. Composite numbers: A002808.

Programs

  • Mathematica
    cc[x_]:=FromDigits[Flatten[IntegerDigits/@x]]; Module[{nn= 100,cmps,tr,len},cmps = Select[Range[nn],CompositeQ];len=Length[cmps];tr = Floor[ (Sqrt[1+8 len]-1)/2];cc/@TakeList[cmps,Range[tr]]] (* Harvey P. Dale, Sep 26 2021 *)

A137318 Concatenation of segments of the digit sequence 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3 1 3....

Original entry on oeis.org

1, 31, 313, 1313, 13131, 313131, 3131313, 13131313, 131313131, 3131313131, 31313131313, 131313131313, 1313131313131, 31313131313131, 313131313131313, 1313131313131313, 13131313131313131, 313131313131313131
Offset: 1

Views

Author

Ctibor O. Zizka, Apr 06 2008

Keywords

Comments

A000042 is 1,11,111,1111,11111,... concatenation of 111111111111111....
A002276 is 2,22,222,2222,22222,... concatenation of 222222222222222....
A133013 is 2,35,71113,... concatenation of 2 3 5 7 11 13 17 19 23 29,...

Crossrefs

Programs

  • Mathematica
    Module[{nn=20},FromDigits/@TakeList[PadRight[{},(nn(nn+1))/2,{1,3}],Range[ nn]]] (* Harvey P. Dale, Aug 04 2021 *)

Formula

O.g.f.: x*(100x^4 + 200x^3 + 83x^2 + 20x + 1)/((10x-1)(100x^2+1)(x-1)(x^2+1)). - R. J. Mathar, Apr 09 2008

Extensions

More terms from R. J. Mathar, Apr 09 2008
Showing 1-10 of 16 results. Next