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.

A169864 The sequence S of a pair S, T generalizing Golomb's sequence A001462 and the pair A093848, A169863. See Comments for definition.

Original entry on oeis.org

1, 3, 4, 6, 8, 10, 12, 13, 15, 17, 19, 21, 23, 25, 26, 28, 30, 32, 34, 36, 38, 40, 42, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 91, 93
Offset: 1

Views

Author

N. J. A. Sloane, Jun 27 2010, following a posting from Eric Angelini to the Sequence Fans Mailing List, Jun 22, 2010

Keywords

Comments

S is built with the rules [1] that you cannot insert any integer between two "touching" runs (run 1,3 is followed by 4,6,8,10,12; there is no integer between 3 and 4) and [2] that S and T share no integer.
T encodes the instructions for S.
It is not quite clear to me if T is the complement of S, or is merely disjoint from it.

Crossrefs

A169865 The sequence T of a pair S, T generalizing Golomb's sequence A001462 and the pair A093848, A169863. See Comments for definition.

Original entry on oeis.org

2, 5, 7, 9, 11, 14, 16, 18, 20, 22, 24, 27, 29, 31, 33, 35, 37, 39, 41, 44, 46
Offset: 1

Views

Author

N. J. A. Sloane, Jun 27 2010, following a posting from Eric Angelini to the Sequence Fans Mailing List, Jun 22, 2010

Keywords

Comments

S is built with the rules [1] that you cannot insert any integer between two "touching" runs (run 1,3 is followed by 4,6,8,10,12; there is no integer between 3 and 4) and [2] that S and T share no integer.

Crossrefs

A169866 The sequence S of a pair of complementary sequences (S, T) which are similar to the pairs (A093848, A169863), (A169864, A169865), except that here the lengths of the equal-parity runs of one sequence are given by the other.

Original entry on oeis.org

1, 3, 4, 6, 8, 10, 12, 11, 13, 15, 17, 19, 21, 23, 22, 24, 26, 28, 30, 32, 34, 36, 38, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86
Offset: 1

Views

Author

N. J. A. Sloane, Jun 27 2010, following a posting from Eric Angelini to the Sequence Fans Mailing List, Jun 22, 2010

Keywords

Crossrefs

A169867 The sequence T of a pair of complementary sequences (S, T) which are similar to the pairs (A093848, A169863), (A169864, A169865), except that here the lengths of the equal-parity runs of one sequence are given by the other.

Original entry on oeis.org

2, 5, 7, 9, 14, 16, 18, 20, 25, 27, 29, 31, 33, 35, 40, 42, 44, 46, 48, 50, 52, 54, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110
Offset: 1

Views

Author

N. J. A. Sloane, Jun 27 2010, following a posting from Eric Angelini to the Sequence Fans Mailing List, Jun 22, 2010

Keywords

Crossrefs

A093848 (a(n)) is the earliest monotonic sequence starting with a(1)=1 and satisfying a(n)=length of n-th run of consecutive integers with same parity.

Original entry on oeis.org

1, 2, 4, 5, 7, 9, 11, 12, 14, 16, 18, 20, 21, 23, 25, 27, 29, 31, 33, 34, 36, 38, 40, 42, 44, 46, 48, 50, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 122, 124
Offset: 1

Views

Author

Benoit Cloitre, May 21 2004

Keywords

Comments

There are a(1) odd terms, a(2) even terms, a(3) odd terms, a(4) even terms ... - Benoit Cloitre, May 26 2004
A variation on Golomb's sequence A001462.

Examples

			Sequence begins: (1),(2,4),(5,7,9,11),(12,14,16,18,20),(21,.... since the number of elements in each run of odd or even integers is 1, 2, 4, 5, ... the sequence itself.
		

Crossrefs

Programs

  • Maple
    A093848 := proc(nmax) local n,par,a,alast,j ; n := 3 ; par := 1 ; a := [1,2,4] ; while nops(a) < nmax do alast := op(-1,a); if type(alast,'even') = type(par,'even') then ; else alast := alast -1 ; end if; for j from 1 to op(n,a) do a := [op(a), alast+2*j] ; end do: par := 1-par ; n := n+1 ; end do: a ; end proc: A093848(120) ; # R. J. Mathar, Jun 22 2010
  • Mathematica
    t={1,2,4}; Do[t=Join[t,Table[t[[-1]]+2*i-1, {i,t[[n]]}]], {n,3,40}]

Formula

it seems that a(n) = 2n - a*n^b + o(n^b) where a and b are 2 suitable constants. b=0.4.... Does b=2-phi where phi is the golden ratio?

Extensions

Terms starting at a(52) corrected by R. J. Mathar, Jun 22 2010
Showing 1-5 of 5 results.