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.

User: Aviezri S. Fraenkel

Aviezri S. Fraenkel's wiki page.

Aviezri S. Fraenkel has authored 11 sequences. Here are the ten most recent ones:

A080241 Define two sequences by A_n = mex{A_i,B_i : 0 <= i < n} for n >= 0, B_0=0, B_1=1 and for n >= 2, B_n = 2B_{n-1}+(-1)^{A_n}. Sequence gives B_n.

Original entry on oeis.org

0, 1, 3, 7, 13, 27, 55, 109, 219, 437, 875, 1751, 3501, 7003, 14005, 28011, 56021, 112043, 224085, 448171, 896341, 1792683, 3585365, 7170731, 14341463, 28682925, 57365851, 114731701, 229463403, 458926805, 917853611, 1835707221
Offset: 0

Author

Aviezri S. Fraenkel, Mar 12 2003

Keywords

Comments

The minimal excluded value of set of nonnegative numbers S is mex S = least nonnegative integer not in S.
The sequence A_n is given in A080240.

Crossrefs

Cf. A080240.

Extensions

More terms from John W. Layman, May 04 2004

A080240 Define two sequences by A_n = mex{A_i,B_i : 0 <= i < n} for n >= 0, B_0=0, B_1=1 and for n >= 2, B_n = 2B_{n-1}+(-1)^{A_n}. Sequence gives A_n.

Original entry on oeis.org

0, 1, 2, 4, 5, 6, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76
Offset: 0

Author

Aviezri S. Fraenkel, Mar 12 2003

Keywords

Comments

The minimal excluded value of set of nonnegative numbers S is mex S = least nonnegative integer not in S.
The sequence B_n is given in A080241.

Crossrefs

Cf. A080241.

Extensions

More terms from Emeric Deutsch, Apr 13 2005

A045682 Extension of Beatty sequence; complement of A045681.

Original entry on oeis.org

0, 5, 10, 15, 20, 27, 32, 37, 42, 49, 54, 59, 64, 71, 76, 81, 86, 93, 98, 103, 108, 113, 118, 125, 130, 135, 140, 147, 152, 157, 162, 169, 174, 179, 184, 191, 196, 201, 206, 211, 216, 223, 228, 233, 238, 245, 250, 255, 260, 267, 272, 277, 282, 289, 294, 299
Offset: 0

Keywords

Comments

(s,t)-sequences; the case s=2, t=3.

Crossrefs

Programs

  • Mathematica
    s=2; t=3;
    mex:=First[Complement[Range[1,Max[#1]+1],#1]]&;
    a[0]=0; b[n_]:=b[n]=s*a[n]+t*n;
    a[n_]:=a[n]=mex[Flatten[Table[{a[i],b[i]},{i,0,n-1}]]];
    Table[a[n],{n,200}] (* A045681 *)
    Table[b[n],{n,200}] (* A045682 *)
    (* From Clark Kimberling, Apr 02 2011 *)

Formula

a(n) = 2*A045681(n)+3*n.

A045681 Extension of Beatty sequence; complement of A045682.

Original entry on oeis.org

0, 1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 13, 14, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 33, 34, 35, 36, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 55, 56, 57, 58, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 72, 73
Offset: 0

Keywords

Comments

(s,t)-sequences; the case s=2, t=3.

References

  • Clark Kimberling, Complementary Equations, Journal of Integer Sequences, Vol. 10 (2007), Article 07.1.4.

Crossrefs

Programs

  • Mathematica
    s=2; t=3;
    mex:=First[Complement[Range[1,Max[#1]+1],#1]]&;
    a[0]=0; b[n_]:=b[n]=s*a[n]+t*n;
    a[n_]:=a[n]=mex[Flatten[Table[{a[i],b[i]},{i,0,n-1}]]];
    Table[a[n],{n,200}] (* A045681 *)
    Table[b[n],{n,200}] (* A045682 *)
    (* From Clark Kimberling, Apr 02 2011 *)

Formula

a(n)=mex {a(i), b(i):0<=iA045682, mex S=least integer >= 0 not in the sequence S.

A045775 Extension of Beatty sequence; complement of A045774.

Original entry on oeis.org

0, 5, 10, 15, 20, 28, 33, 38, 43, 51, 56, 61, 66, 74, 79, 84, 89, 97, 102, 107, 112, 117, 122, 127, 135, 140, 145, 150, 158, 163, 168, 173, 181, 186, 191, 196, 204, 209, 214, 219, 224, 229, 234, 242, 247, 252, 257, 265, 270, 275, 280, 288, 293, 298, 303
Offset: 0

Keywords

Comments

(s,t)-sequences; the case s=3, t=2.

References

  • Clark Kimberling, Complementary Equations, Journal of Integer Sequences, Vol. 10 (2007), Article 07.1.4.

Crossrefs

Programs

  • Mathematica
    s=3; t=2;
    mex:=First[Complement[Range[1,Max[#1]+1],#1]]&;
    a[0]=0; b[n_]:=b[n]=s*a[n]+t*n;
    a[n_]:=a[n]=mex[Flatten[Table[{a[i],b[i]},{i,0,n-1}]]];
    Table[a[n],{n,200}] (* A045774 *)
    Table[b[n],{n,200}] (* A045775 *)
    (* From Clark Kimberling, Apr 02 2011 *)

Formula

a(n) = 3*A045774(n)+2*n.

A045671 Extension of Beatty sequence; complement of A045672.

Original entry on oeis.org

0, 1, 2, 3, 5, 6, 7, 9, 10, 11, 13, 14, 15, 16, 17, 19, 20, 21, 23, 24, 25, 27, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 45, 47, 48, 49, 51, 52, 53, 55, 56, 57, 59, 60, 61, 63, 64, 65, 66, 67, 69, 70
Offset: 0

Keywords

Comments

Sequence can also be characterized by a special numeration system-see above reference.
(s,t)-sequences; the case s=2, t=2.
For n>=1, these are the positions of 1 in the fixed point of the morphism 0->11, 1->1110; see A285671. Conjecture: -1 < n*r - a(n) < 2 for n>=0, where r = (1 + sqrt(17))/4. - Clark Kimberling, May 02 2017

Crossrefs

Programs

  • Mathematica
    s=2; t=2;
    mex:=First[Complement[Range[1,Max[#1]+1],#1]]&;
    a[0]=0; b[n_]:=b[n]=s*a[n]+t*n;
    a[n_]:=a[n]=mex[Flatten[Table[{a[i],b[i]},{i,0,n-1}]]];
    Table[a[n],{n,200}] (* A045671 *)
    Table[b[n],{n,200}] (* A045672 *)
    (* Clark Kimberling, Apr 02 2011 *)
    s = Nest[Flatten[# /. {0 -> {1, 1}, 1 -> {1, 1, 1, 0}}] &, {0}, 10]; (* A285671 *)
    Flatten[Position[s, 0]];  (* A045672 *)
    Flatten[Position[s, 1]];  (* A045671 *)
    (* - Clark Kimberling, May 02 2017 *)

Formula

a(n) = mex{a(i), b(i):0 <= iA045672, mex S=least integer >= 0 not in sequence S.
a(n) = (1+sqrt(17))/4*n+O(1). - Benoit Cloitre, Apr 23 2008

A045749 Extension of Beatty sequence; complement of A045750.

Original entry on oeis.org

0, 1, 2, 3, 5, 6, 7, 9, 10, 11, 13, 14, 15, 16, 17, 18, 20, 21, 22, 24, 25, 26, 28, 29, 30, 31, 32, 33, 35, 36, 37, 39, 40, 41, 43, 44, 45, 46, 47, 48, 50, 51, 52, 54, 55, 56, 58, 59, 60, 62, 63, 64, 66, 67, 68
Offset: 0

Keywords

Comments

(s,t)-sequences; the case s=3, t=1.
Complement of A045750. It appears likely that A045749(n)=A187570(n) for all n>=1; the equation has been verified for n up to 500. - Clark Kimberling, Apr 02 2011

Crossrefs

Programs

  • Mathematica
    s=3; t=1;
    mex:=First[Complement[Range[1,Max[#1]+1],#1]]&;
    a[0]=0; b[n_]:=b[n]=s*a[n]+t*n;
    a[n_]:=a[n]=mex[Flatten[Table[{a[i],b[i]},{i,0,n-1}]]];
    Table[a[n],{n,200}] (* A045749 *)
    Table[b[n],{n,200}] (* A045750 *)
    (* Clark Kimberling, Apr 02 2011 *)

Formula

a(n) = mex {a(i), b(i):0 <= iA045750, mex S=least integer >= 0 not in the sequence S.

A045750 Extension of Beatty sequence, complement of A045749.

Original entry on oeis.org

0, 4, 8, 12, 19, 23, 27, 34, 38, 42, 49, 53, 57, 61, 65, 69, 76, 80, 84, 91, 95, 99, 106, 110, 114, 118, 122, 126, 133, 137, 141, 148, 152, 156, 163, 167, 171, 175, 179, 183, 190, 194, 198, 205, 209, 213, 220, 224, 228, 235, 239, 243, 250, 254, 258
Offset: 0

Keywords

Comments

(s,t)-sequences; the case s=3, t=1.
Complement of A187749. It appears likely that A045750(n)=A187571(n) for all n>=1; the equation has been verified for n up to 500. - Clark Kimberling, Apr 02 2011

Crossrefs

Programs

  • Mathematica
    s=3; t=1;
    mex:=First[Complement[Range[1, Max[#1]+1], #1]]&;
    a[0]=0; b[n_]:=b[n]=s*a[n]+t*n;
    a[n_]:=a[n]=mex[Flatten[Table[{a[i], b[i]}, {i, 0, n-1}]]];
    Table[a[n], {n, 200}] (* A045749 *)
    Table[b[n], {n, 200}] (* A045750 *)
    (* Clark Kimberling, Apr 02 2011 *)

Formula

a(n) = 3*A045749(n) + n.

A045774 Extension of Beatty sequence; complement of A045775.

Original entry on oeis.org

0, 1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 13, 14, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 34, 35, 36, 37, 39, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 57, 58, 59, 60, 62, 63, 64, 65
Offset: 0

Keywords

Comments

(s,t)-sequences; the case s=3, t=2.

Crossrefs

Programs

  • Mathematica
    s=3; t=2;
    mex:=First[Complement[Range[1,Max[#1]+1],#1]]&;
    a[0]=0; b[n_]:=b[n]=s*a[n]+t*n;
    a[n_]:=a[n]=mex[Flatten[Table[{a[i],b[i]},{i,0,n-1}]]];
    Table[a[n],{n,200}] (* A045774 *)
    Table[b[n],{n,200}] (* A045775 *)
    (* Clark Kimberling, Apr 02 2011 *)

Formula

a(n)=mex {a(i), b(i):0 <= iA045775, mex S=least integer >= 0 not in the sequence S.

A038150 Array of numbers used in exotic ternary numeration system, read by antidiagonals.

Original entry on oeis.org

1, 2, 3, 4, 6, 8, 5, 11, 16, 21, 7, 14, 29, 42, 55, 9, 19, 37, 76, 110, 144, 10, 24, 50, 97, 199, 288, 377, 12, 27, 63, 131, 254, 521, 754, 987, 13, 32, 71, 165, 343, 665, 1364, 1974, 2584, 15, 35, 84, 186, 432, 898, 1741, 3571, 5168, 6765, 17, 40, 92, 220, 487
Offset: 0

Keywords

Examples

			Top left corner of array:
  1,  3,  8, 21,  55, ...
  2,  6, 16, 42, 110, ...
  4, 11, 29, 76, 199, ...
  5, 14, 37, 97, 254, ...
		

Crossrefs

Rows give A001906, A025169, A002878.
Columns give A026351, A047924, A047925.
Main diagonal gives A047923.

Programs

  • Mathematica
    t[n_, 1] := Floor[(n - 1) GoldenRatio] + 1; t[n_, j_] := Floor[ GoldenRatio^2 t[n, j - 1]] + 1; Table[ t[n - m + 1, m], {n, 11}, {m, n}] // Flatten (* Birkas Gyorgy, Apr 15 2011; modified by Robert G. Wilson v, Apr 15 2011 *)

Formula

For n >= 0, A_0^n is the least nonnegative integer not in {A_j^n: 0 <= i < n, j >= 0, A_1^n = 2A_0^n + n, A_j^n = 3A_{j-1}^n - A_{j-2}^n (j >= 2).
a(n,k) = F(2k)*n + F(2k+1)*A026351(n). - Charlie Neder, Feb 07 2019

Extensions

More terms from Naohiro Nomoto, Jun 07 2001