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 1-3 of 3 results.

A111986 Number of numbers having n quadratic residues.

Original entry on oeis.org

1, 3, 2, 5, 0, 5, 2, 6, 2, 1, 2, 12, 0, 4, 1, 6, 0, 6, 1, 3, 4, 7, 1, 17, 0, 0, 3, 7, 0, 6, 2, 6, 3, 1, 0, 15, 1, 3, 0, 6, 0, 11, 0, 14, 3, 1, 0, 24, 2, 0, 1, 1, 1, 10, 1, 8, 3, 0, 0, 13, 0, 5, 5, 7, 0, 10, 0, 3, 2, 3, 0, 26, 0, 3, 1, 6, 4, 0, 2, 9, 3, 1, 0, 25, 0, 0, 2, 18, 0, 13, 1, 3, 4, 0, 0, 26
Offset: 1

Views

Author

T. D. Noe, Aug 25 2005

Keywords

Examples

			a(4)=5 because the numbers 6, 7, 9, 12 and 16 each have 4 quadratic residues.

Crossrefs

Cf. A037041 (n such that a(n)>0), A037046 (n such that a(n)=0), A111987 (least number having n quadratic residues), A111988 (greatest number having n quadratic residues).

Programs

  • Mathematica
    t=Table[Length[Union[Mod[Range[0, n/2]^2, n]]], {n, 10000}]; Table[Length[Position[t, n]], {n, 100}]

A111987 Least number having n quadratic residues, or 0 if there is no number.

Original entry on oeis.org

1, 2, 5, 6, 0, 10, 13, 14, 17, 19, 25, 22, 0, 26, 29, 31, 0, 34, 37, 38, 41, 43, 128, 46, 0, 0, 53, 78, 0, 58, 61, 62, 135, 67, 0, 71, 73, 74, 0, 79, 0, 82, 0, 86, 89, 384, 0, 94, 97, 0, 101, 103, 125, 106, 109, 121, 113, 0, 0, 118, 0, 122, 205, 127, 0, 131, 0, 134, 137, 139, 0
Offset: 1

Views

Author

T. D. Noe, Aug 25 2005

Keywords

Examples

			a(4)=6 because, of the five numbers having 4 quadratic residues (6,7,9,12,16), the least is 6.

Crossrefs

Cf. A037046 (n such that a(n)=0), A111986 (number of numbers having n quadratic residues), A111988 (greatest number having n quadratic residues).

Programs

  • Mathematica
    t=Table[Length[Union[Mod[Range[0, n/2]^2, n]]], {n, 10000}]; Table[pos=Flatten[Position[t, n]]; If[Length[pos]==0, 0, First[pos]], {n, 100}]

A111988 Greatest number having n quadratic residues, or 0 if there is no such number.

Original entry on oeis.org

1, 4, 8, 16, 0, 24, 32, 48, 40, 19, 27, 80, 0, 96, 29, 144, 0, 120, 37, 76, 160, 108, 128, 240, 0, 0, 136, 288, 0, 152, 81, 336, 216, 67, 0, 360, 73, 148, 0, 304, 0, 480, 0, 432, 232, 384, 0, 720, 416, 0, 101, 103, 125, 440, 109, 672, 296, 0, 0, 464, 0, 324, 544, 1008, 0
Offset: 1

Views

Author

T. D. Noe, Aug 25 2005

Keywords

Examples

			a(4)=16 because, of the five numbers having 4 quadratic residues (6,7,9,12,16), the greatest is 16.

Crossrefs

Cf. A037046 (n such that a(n)=0), A111986 (number of numbers having n quadratic residues), A111987 (least number having n quadratic residues).

Programs

  • Mathematica
    t=Table[Length[Union[Mod[Range[0, n/2]^2, n]]], {n, 10000}]; Table[pos=Flatten[Position[t, n]]; If[Length[pos]==0, 0, Last[pos]], {n, 100}]
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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