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 20 results. Next

A095029 An example of a (v,k,lambda)=(21,5,1) cyclic difference set.

Original entry on oeis.org

3, 6, 7, 12, 14
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

A (v,k,lambda) cyclic difference set is a subset D={d_1,d_2,...,d_k} of the integers modulo v such that {1,2,...,v-1} can each be represented as a difference (d_i-d_j) modulo v in exactly lambda different ways. Difference sets with lambda=1 (planar difference sets) have order n=k-1. The Prime Power Conjecture states that all Abelian planar difference sets have order n a prime power. It is known that no cyclic planar difference sets of nonprime power order n exist with n < 2*10^9 (see Baumert, Gordon link)

Examples

			Representation of {1,...,20}: 1=7-6, 2=14-12, 3=6-3, 4=7-3, 5=12-7, 6=12-6, 7=14-7, 8=14-6, 9=12-3, 10=21+3-14, 11=14-3, 12=21+3-12, 13=21+6-14, 14=21+7-14, 15=21+6-12, 16=21+7-12, 17=21+3-7, 18=21+3-6, 19=21+12-14, 20=21+6-7. - _Hugo Pfoertner_, Aug 13 2011
		

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095047 (more examples of cyclic difference set with k=5..20), A000961 (prime powers).

A095047 An example of a (v,k,lambda)=(107,53,26) cyclic difference set.

Original entry on oeis.org

1, 3, 4, 9, 10, 11, 12, 13, 14, 16, 19, 23, 25, 27, 29, 30, 33, 34, 35, 36, 37, 39, 40, 41, 42, 44, 47, 48, 49, 52, 53, 56, 57, 61, 62, 64, 69, 75, 76, 79, 81, 83, 85, 86, 87, 89, 90, 92, 99, 100, 101, 102, 105
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

See A095029. This is an example of a difference set that produces a large number of different representations.

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095046 (more examples of cyclic difference sets with k=5..20).

A095028 An example of a (v,k,lambda)=(11,5,2) cyclic difference set.

Original entry on oeis.org

1, 3, 4, 5, 9
Offset: 1

Views

Author

Hugo Pfoertner, Jun 02 2004

Keywords

Comments

See A095029.

Examples

			Using the numbers {1 3 4 5 9}, every number in the range 1..10 can be written as a difference modulo 11 in two different ways:
1=4-3=5-4, 2=3-1=5-3, 3=4-1=(1-9) mod 11, 4=5-1=9-5, 5=9-4=(3-9) mod 11,
6=9-2=(4-9) mod 11, 7=(1-5) mod 11=(5-9) mod 11, 8=9-1=(1-4) mod 11,
9=(1-3) mod 11=(3-5) mod 11, 10=(3-4) mod 11=(4-5) mod 11.
		

Crossrefs

Cf. A095025 number of cyclic difference sets with n elements, A095029 .. A095047 more examples of cyclic difference set with k=5..53.

A095030 An example of a (v,k,lambda)=(31,6,1) cyclic difference set.

Original entry on oeis.org

1, 5, 11, 24, 25, 27
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

See A095029.

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095047 (more examples of cyclic difference set with k=5..20), A000961 (prime powers).

A095032 An example of a (v,k,lambda)=(57,8,1) cyclic difference set.

Original entry on oeis.org

0, 1, 6, 15, 22, 26, 45, 55
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

See A095029.

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095047 (more examples of cyclic difference sets with k=5..20), A000961 (prime powers).

A095035 An example of a (v,k,lambda)=(73,9,1) cyclic difference set.

Original entry on oeis.org

0, 1, 12, 20, 26, 30, 33, 35, 57
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

See A095029.

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095047 (more examples of cyclic difference sets with k=5..20), A000961 (prime powers).

A095036 An example of a (v,k,lambda)=(91,10,1) cyclic difference set.

Original entry on oeis.org

0, 2, 6, 7, 18, 21, 31, 54, 63, 71
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

See A095029.

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095047 (more examples of cyclic difference sets with k=5..20), A000961 (prime powers).

A095038 An example of a (v,k,lambda)=(133,12,1) cyclic difference set.

Original entry on oeis.org

1, 10, 11, 13, 27, 31, 68, 75, 83, 110, 115, 121
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

See A095029.

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095047 (more examples of cyclic difference sets with k=5..20), A000961 (prime powers).

A095040 An example of a (v,k,lambda)=(183,14,1) cyclic difference set.

Original entry on oeis.org

1, 13, 20, 21, 23, 44, 61, 72, 77, 86, 90, 116, 122, 169
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

See A095029.

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095047 (more examples of cyclic difference sets with k=5..20), A000961 (prime powers).

A095041 One of two (v,k,lambda)=(31,15,7) cyclic difference sets. The other one is A095042.

Original entry on oeis.org

1, 2, 3, 4, 6, 8, 12, 15, 16, 17, 23, 24, 27, 29, 30
Offset: 1

Views

Author

Hugo Pfoertner, May 27 2004

Keywords

Comments

See A095029.

Crossrefs

Cf. A095025 (number of cyclic difference sets with n elements), A095029-A095047 (more examples of cyclic difference sets with k=5..20).
Showing 1-10 of 20 results. Next