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.

A230760 Values of y such that x^2 + y^2 = 53^n with x and y coprime and 0 < x < y.

Original entry on oeis.org

7, 45, 286, 2520, 20122, 148148, 1007606, 6254640, 46181513, 391594275, 3034699661, 21731298679, 143399099473, 855828562635, 7344390292954, 60173627260320, 453178096117918, 3155291100853892, 20155636317704834, 131804682060038201, 1152529734625490207
Offset: 1

Views

Author

Colin Barker, Oct 29 2013

Keywords

Comments

The corresponding x-values are in A230759.

Examples

			a(3)=286 because 259^2+286^2=148877=53^3.
		

Crossrefs

A230841 Values of x such that x^2 + y^2 = 61^n with x and y coprime and 0 < x < y.

Original entry on oeis.org

5, 11, 234, 1320, 9475, 117469, 266286, 9184560, 3302155, 520632300, 1387108806, 23922442439, 154165737965, 933420304380, 13338456688674, 22995028210081, 1026964091673115, 713853567388260, 54078566783400895, 171226928056302601, 2435077776719657394
Offset: 1

Views

Author

Colin Barker, Oct 31 2013

Keywords

Comments

The corresponding y-values are in A230842.

Examples

			a(3)=234 because 234^2+415^2=226981=61^3.
		

Crossrefs

Programs

  • Mathematica
    Table[Select[PowersRepresentations[61^n, 2, 2], CoprimeQ[#[[1]], #[[2]]] &][[1, 1]], {n, 22}] (* T. D. Noe, Nov 04 2013 *)
    Table[Select[PowersRepresentations[61^n, 2, 2], CoprimeQ@@#&][[1, 1]], {n, 1, 40}] (* Vincenzo Librandi, Mar 02 2014 *)

Extensions

a(10) and a(20) corrected by Zak Seidov, Nov 02 2013

A230962 Values of x such that x^2 + y^2 = 73^n with x and y coprime and 0 < x < y.

Original entry on oeis.org

3, 48, 296, 721, 10072, 213785, 1958709, 7613760, 21165597, 894454032, 12278087704, 59926173839, 62518379032, 3374316625735, 58552907681096, 416603004343680, 1261259807092797, 10231862403603888, 255781764375436389, 2697529798981443601, 11543491568219853608
Offset: 1

Views

Author

Colin Barker, Nov 02 2013

Keywords

Comments

The corresponding y-values are in A230963.

Examples

			a(3) = 296 because 296^2 + 549^2 = 389017 = 73^3.
		

Crossrefs

Programs

  • Maple
    f:=n ->  min([abs@Re,abs@Im]((3+8*I)^n)):
    map(f, [$1..50]); # Robert Israel, Mar 31 2017
  • Mathematica
    Table[Select[PowersRepresentations[73^n, 2, 2], CoprimeQ@@#&][[1, 1]], {n, 1, 40}] (* Vincenzo Librandi, Mar 02 2014 *)
    Table[Min[Abs[Re[(3 + 8I)^n]], Abs[Im[(3 + 8I)^n]]], {n, 30}] (* Indranil Ghosh, Mar 31 2017, after formula by Robert Israel *)
  • Python
    from sympy import I, re, im
    print([min(abs(re((3 + 8*I)**n)), abs(im((3 + 8*I)**n))) for n in range(1, 31)]) # Indranil Ghosh, Mar 31 2017, after formula by Robert Israel

Formula

From Robert Israel, Mar 31 2017: (Start)
a(n) = min(abs(Re((3+8i)^n)), abs(Im((3+8i)^n))).
a(n) = abs(Re(3+8i)^n) if and only if 1/4 < frac(n*arctan(8/3)/Pi) < 3/4.
(End)
Showing 1-3 of 3 results.