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.

A001543 a(0) = 1, a(n) = 5 + Product_{i=0..n-1} a(i) for n > 0.

Original entry on oeis.org

1, 6, 11, 71, 4691, 21982031, 483209576974811, 233491495280173380882643611671, 54518278368171228201482876236565907627201914279213829353891
Offset: 0

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Author

Keywords

Comments

This is the special case k=5 of sequences with exact mutual k-residues. In general, a(1)=k+1 and a(n)=min{m | m>a(n-1), mod(m,a(i))=k, i=1,...,n-1}. k=1 gives Sylvester's sequence A000058 and k=2 Fermat sequence A000215. - Seppo Mustonen, Sep 04 2005

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column k=5 of A177888.

Programs

  • Mathematica
    Flatten[{1,RecurrenceTable[{a[1]==6, a[n]==a[n-1]*(a[n-1]-5)+5}, a, {n, 1, 10}]}] (* Vaclav Kotesovec, Dec 17 2014 *)
    Join[{1},NestList[#(#-5)+5&,6,10]] (* Harvey P. Dale, Oct 10 2016 *)
  • PARI
    {
      print1("1, 6");
      n=6;
      m=Mod(5,6);
      for(i=2,9,
        n=m.mod+lift(m);
        m=chinese(m,Mod(5,n));
        print1(", "n)
      )
    } \\ Charles R Greathouse IV, Dec 09 2011

Formula

a(n) = a(n-1) * (a(n-1) - 5) + 5. - Charles R Greathouse IV, Dec 09 2011
a(n) ~ c^(2^n), where c = 1.696053774403103324180661918166106455311376345474042496749974632237971081462... . - Vaclav Kotesovec, Dec 17 2014

Extensions

New name from Alonso del Arte, Dec 09 2011

A001544 A nonlinear recurrence: a(n) = a(n-1)^2 - 6*a(n-1) + 6, with a(0) = 1, a(1) = 7.

Original entry on oeis.org

1, 7, 13, 97, 8833, 77968897, 6079148431583233, 36956045653220845240164417232897, 1365749310322943329964576677590044473746108255675592519835615233
Offset: 0

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Author

Keywords

Comments

This is the special case k=6 of sequences with exact mutual k-residues. In general, a(1)=k+1 and a(n)=min{m | m>a(n-1), mod(m,a(i))=k, i=1,...,n-1}. k=1 gives Sylvester's sequence A000058 and k=2 Fermat sequence A000215. - Seppo Mustonen, Sep 04 2005

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Column k=6 of A177888. - Alois P. Heinz, Nov 07 2012

Programs

  • Mathematica
    Flatten[{1,RecurrenceTable[{a[1]==7, a[n]==a[n-1]*(a[n-1]-6)+6}, a, {n, 1, 10}]}] (* Vaclav Kotesovec, Dec 17 2014 *)
    Join[{1},NestList[#^2-6#+6&,7,10]] (* Harvey P. Dale, Nov 19 2024 *)
  • PARI
    a(n)=if(n<1, n==0, if(n==1, 7, n=a(n-1); n^2-6*n+6))

Formula

a(n) ~ c^(2^n), where c = 1.76450357631319101484804524709844019487003729926754942591419313922841785792... . - Vaclav Kotesovec, Dec 17 2014

A067686 a(n) = a(n-1) * a(n-1) - B * a(n-1) + B, a(0) = 1 + B for B = 7.

Original entry on oeis.org

8, 15, 127, 15247, 232364287, 53993160246468367, 2915261353400811631533974206368127, 8498748758632331927648392184620600167779995785955324343380396911247
Offset: 0

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Author

Drastich Stanislav (drass(AT)spas.sk), Feb 05 2002

Keywords

Comments

This is the special case k=7 of sequences with exact mutual k-residues. In general, a(1)=k+1 and a(n)=min{m | m>a(n-1), mod(m,a(i))=k, i=1,...,n-1}. k=1 gives Sylvester's sequence A000058 and k=2 Fermat sequence A000215. - Seppo Mustonen, Sep 04 2005

Crossrefs

Cf. B=1: A000058 (Sylvester's sequence), B=2: A000215 (Fermat numbers), B=3: A000289, B=4: A000324, B=5: A001543, B=6: A001544.
Column k=7 of A177888.

Programs

  • Mathematica
    RecurrenceTable[{a[0]==8, a[n]==a[n-1]*(a[n-1]-7)+7}, a, {n, 0, 10}] (* Vaclav Kotesovec, Dec 17 2014 *)
    NestList[#^2-7#+7&,8,10] (* Harvey P. Dale, Jan 26 2025 *)

Formula

a(n) ~ c^(2^n), where c = 3.3333858371760195832345950846454963835549715770476958790043961891683146201... . - Vaclav Kotesovec, Dec 17 2014

A110360 Integers with mutual residues of 8.

Original entry on oeis.org

9, 17, 161, 24641, 606981761, 368426853330807041, 135738346255240000293762417728719361, 18424898644107427010977107148874723523180059431182608785043639266493441
Offset: 1

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Author

Seppo Mustonen, Sep 04 2005

Keywords

Comments

This is the special case k=8 of sequences with exact mutual k-residues. In general, a(1)=k+1 and a(n)=min{m | m>a(n-1), mod(m,a(i))=k, i=1,...,n-1}. k=1 gives Sylvester's sequence A000058 and k=2 Fermat sequence A000215.

Crossrefs

Column k=8 of A177888.

Programs

  • Mathematica
    RecurrenceTable[{a[1]==9, a[n]==a[n-1]*(a[n-1]-8)+8}, a, {n, 1, 10}] (* Vaclav Kotesovec, Dec 17 2014 *)

Formula

a(n) ~ c^(2^n), where c = 1.8813701045812484604409881785833034768479650739052732570542874567824022000... . - Vaclav Kotesovec, Dec 17 2014

A177701 Triangle of coefficients of polynomials P_n(z) defined by the recursion P_0(z) = z+1; for n>=1, P_n(z) = z + Product_{k=0..n-1} P_k(z).

Original entry on oeis.org

1, 1, 2, 1, 2, 4, 1, 4, 14, 16, 8, 1, 16, 112, 324, 508, 474, 268, 88, 16, 1, 256, 3584, 22912, 88832, 233936, 443936, 628064, 675456, 557492, 353740, 171644, 62878, 17000, 3264, 416, 32, 1, 65536, 1835008, 24576000, 209715200, 1281482752, 5974786048, 22114709504, 66752724992
Offset: 1

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Author

Vladimir Shevelev, Dec 11 2010

Keywords

Comments

Length of the first row is 2; for i>=2, length of the i-th row is 2^{i-2}+1.

Examples

			Triangle begins:
   1,   1;
   2,   1;
   2,   4,   1;
   4,  14,  16,   8,   1;
  16, 112, 324, 508, 474, 268, 88, 16, 1;
  ...
		

Crossrefs

Programs

  • Maple
    p:= proc(n) option remember;
           z-> z+ `if`(n=0, 1, p(n-1)(z)*(p(n-1)(z)-z))
        end:
    deg:= n-> `if`(n=0, 1, 2^(n-1)):
    T:= (n,k)-> coeff(p(n)(z), z, deg(n)-k):
    seq(seq(T(n,k), k=0..deg(n)), n=0..6); # Alois P. Heinz, Dec 13 2010
  • Mathematica
    P[0][z_] := z + 1;
    P[n_][z_] := P[n][z] = z + Product[P[k][z], {k, 0, n-1}];
    row[n_] := CoefficientList[P[n][z], z] // Reverse;
    Table[row[n], {n, 0, 6}] // Flatten (* Jean-François Alcover, Jun 11 2018 *)

Formula

Another recursion is: P_n(z)=z+P_(n-1)(z)(P_(n-1)(z)-z).
Private values: P_n(0)=1; P_n(-1)=delta_(n,0)-1; {P_n(1)}=A000058; {P_n(2)}=A000215; {P_n(3)}={A000289(n+1)}; {P_n(4)}={A000324(n+1)}; {P_n(5)}={A001543(n+1)}; {P_n(6)}={A001544(n+1)}; {P_n(7)}={A067686(n)}; {P_n(8)}={A110360(n)}; {P_0(n)}={A000027(n+1)}; {P_1(n)}={A005408(n)}; {P_2(n)}={A056220(n+1)}.

Extensions

More terms from Alois P. Heinz, Dec 13 2010

A252730 a(n) = P_n(n) with P_0(z) = z+1 and P_n(z) = z + P_{n-1}(z)*(P_{n-1}(z)-z) for n>1.

Original entry on oeis.org

1, 3, 17, 871, 4870849, 483209576974811, 36956045653220845240164417232897, 8498748758632331927648392184620600167779995785955324343380396911247
Offset: 0

Views

Author

Alois P. Heinz, Dec 20 2014

Keywords

Crossrefs

Main diagonal of A177888.

Programs

  • Maple
    p:= proc(n) option remember;
          z-> z+ `if`(n=0, 1, p(n-1)(z)*(p(n-1)(z)-z))
        end:
    a:= n-> p(n)(n):
    seq(a(n), n=0..8);
  • Mathematica
    p[n_] := p[n] = Function[z, z + If[n == 0, 1, p[n-1][z]*(p[n-1][z] - z)]];
    a[n_] := p[n][n];
    Table[a[n], {n, 0, 8}] (* Jean-François Alcover, Jun 12 2018, from Maple *)

A110368 Integers with mutual residues of 9.

Original entry on oeis.org

10, 19, 199, 37819, 1429936399, 2044718092315659619, 4180872077042990313463432060226288599, 17479691324597767931283328689425028720038746822457352536058485868000785419
Offset: 1

Views

Author

Seppo Mustonen, Sep 04 2005

Keywords

Comments

This is the special case k=9 of sequences with exact mutual k-residues. In general, a(1)=k+1 and a(n)=min{m | m>a(n-1), mod(m,a(i))=k, i=1,...,n-1}. k=1 gives Sylvester's sequence A000058 and k=2 Fermat sequence A000215.

Crossrefs

Column k=9 of A177888.

Programs

  • Mathematica
    RecurrenceTable[{a[1]==10, a[n]==a[n-1]*(a[n-1]-9)+9}, a, {n, 1, 10}] (* Vaclav Kotesovec, Dec 17 2014 *)

Formula

a(n) ~ c^(2^n), where c = 1.9324294501525084771045650938374200605001383645783351474944965038078432359... . - Vaclav Kotesovec, Dec 17 2014

A110383 Integers with mutual residues of 10.

Original entry on oeis.org

11, 21, 241, 55681, 3099816961, 9608865160705105921, 92330289676612360941221747472778199041, 8524882391767151111154918892947398067446166736305624023874497267723631329281
Offset: 1

Views

Author

Seppo Mustonen, Sep 04 2005

Keywords

Comments

This is the special case k=10 of sequences with exact mutual k-residues. In general, a(1)=k+1 and a(n)=min{m | m>a(n-1), mod(m,a(i))=k, i=1..n-1}. k=1 gives Sylvester's sequence A000058 and k=2 Fermat sequence A000215.

Crossrefs

Column k=10 of A177888.

Programs

  • Mathematica
    RecurrenceTable[{a[1]==11, a[n]==a[n-1]*(a[n-1]-10)+10}, a, {n, 1, 10}] (* Vaclav Kotesovec, Dec 17 2014 *)

Formula

a(n) ~ c^(2^n), where c = 1.9797221926746931491020959969764290497942241392143973226882604062455515473... . - Vaclav Kotesovec, Dec 17 2014
Showing 1-8 of 8 results.