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.

A080590 a(1)=1; for n>1, a(n)=a(n-1)+3 if n is already in the sequence, a(n)=a(n-1)+4 otherwise.

Original entry on oeis.org

1, 5, 9, 13, 16, 20, 24, 28, 31, 35, 39, 43, 46, 50, 54, 57, 61, 65, 69, 72, 76, 80, 84, 87, 91, 95, 99, 102, 106, 110, 113, 117, 121, 125, 128, 132, 136, 140, 143, 147, 151, 155, 158, 162, 166, 169, 173, 177, 181, 184, 188, 192, 196, 199, 203, 207
Offset: 1

Views

Author

N. J. A. Sloane, Mar 23 2003

Keywords

Comments

In the Fokkink-Joshi paper, this sequence is the Cloitre (0,1,3,4)-hiccup sequence. - Michael De Vlieger, Jul 29 2025

Crossrefs

Programs

  • Haskell
    a080590 n = a080590_list !! (n-1)
    a080590_list = 1 : f 2 [1] where
       f x zs@(z:_) = y : f (x + 1) (y : zs) where
         y = z + (if x `elem` zs then 3 else 4)
    -- Reinhard Zumkeller, Sep 26 2014
  • Mathematica
    a[n_] := a[n] = If[n == 1, 1, If[MemberQ[Array[a, n-1], n], a[n-1]+3, a[n-1]+4]]; Array[a, 56] (* Jean-François Alcover, Oct 05 2018 *)

A081840 a(1)=0, a(n)=a(n-1)+3 if n is already in the sequence, a(n)=a(n-1)+4 otherwise.

Original entry on oeis.org

0, 4, 8, 11, 15, 19, 23, 26, 30, 34, 37, 41, 45, 49, 52, 56, 60, 64, 67, 71, 75, 79, 82, 86, 90, 93, 97, 101, 105, 108, 112, 116, 120, 123, 127, 131, 134, 138, 142, 146, 149, 153, 157, 161, 164, 168, 172, 176, 179, 183, 187, 190, 194, 198, 202, 205, 209, 213, 217
Offset: 1

Views

Author

Benoit Cloitre, Apr 11 2003

Keywords

Comments

In the Fokkink-Joshi paper, this sequence is the Cloitre (0,0,3,4)-hiccup sequence. - Michael De Vlieger, Jul 29 2025

Crossrefs

Programs

Formula

a(n) = floor(r*n-(2*r+1)/(r-1)) where r = 2+sqrt(3).

A081841 a(1)=0, a(n)=a(n-1)+3 if n is already in the sequence, a(n)=a(n-1)+2 otherwise.

Original entry on oeis.org

0, 2, 4, 7, 9, 11, 14, 16, 19, 21, 24, 26, 28, 31, 33, 36, 38, 40, 43, 45, 48, 50, 52, 55, 57, 60, 62, 65, 67, 69, 72, 74, 77, 79, 81, 84, 86, 89, 91, 94, 96, 98, 101, 103, 106, 108, 110, 113, 115, 118, 120, 123, 125, 127, 130, 132, 135, 137, 139, 142, 144, 147, 149, 151
Offset: 1

Views

Author

Benoit Cloitre, Apr 11 2003

Keywords

Comments

In the Fokkink-Joshi paper, this sequence is the Cloitre (0,0,3,2)-hiccup sequence. - Michael De Vlieger, Jul 29 2025

Crossrefs

Programs

Formula

a(1)=0; for n>=1 a(n)=floor(r*n-(4*r-1)/(r+1)) where r=1+sqrt(2)

A081842 a(1)=0, a(n)=a(n-1)+4 if n is already in the sequence, a(n)=a(n-1)+3 otherwise.

Original entry on oeis.org

0, 3, 7, 10, 13, 16, 20, 23, 26, 30, 33, 36, 40, 43, 46, 50, 53, 56, 59, 63, 66, 69, 73, 76, 79, 83, 86, 89, 92, 96, 99, 102, 106, 109, 112, 116, 119, 122, 125, 129, 132, 135, 139, 142, 145, 149, 152, 155, 158, 162, 165, 168, 172, 175, 178, 182, 185, 188, 192, 195
Offset: 1

Views

Author

Benoit Cloitre, Apr 11 2003

Keywords

Comments

In the Fokkink-Joshi paper, this sequence is the Cloitre (0,0,4,3)-hiccup sequence. - Michael De Vlieger, Jul 29 2025

Crossrefs

Programs

  • Mathematica
    Module[{seq={0},n=2},Do[If[MemberQ[seq,n],AppendTo[seq,Last[seq]+4],AppendTo[seq, Last[seq]+3]];n++,{60}];seq] (* Harvey P. Dale, Nov 20 2012 *)

Formula

a(n) = floor(r*n-(4*r-1)/(r+1)) where r = (1/2)*(3+sqrt(13)).

A081839 a(1)=0, a(n)=a(n-1)+4 if n is already in the sequence, a(n)=a(n-1)+5 otherwise.

Original entry on oeis.org

0, 5, 10, 15, 19, 24, 29, 34, 39, 43, 48, 53, 58, 63, 67, 72, 77, 82, 86, 91, 96, 101, 106, 110, 115, 120, 125, 130, 134, 139, 144, 149, 154, 158, 163, 168, 173, 178, 182, 187, 192, 197, 201, 206, 211, 216, 221, 225, 230, 235, 240, 245, 249, 254, 259, 264, 269
Offset: 1

Views

Author

Benoit Cloitre, Apr 11 2003

Keywords

Comments

In the Fokkink-Joshi paper, this sequence is the Cloitre (0,0,4,5)-hiccup sequence. - Michael De Vlieger, Jul 29 2025

Crossrefs

Programs

Formula

a(n) = floor(r*n-(3*r+1)/(r-1)) where r = (1/2) *(5+sqrt(21)) = 4.79128784747792...
Showing 1-5 of 5 results.