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 17 results. Next

A088319 Ordered hypotenuses of primitive Pythagorean triangles having legs that add up to a square.

Original entry on oeis.org

41, 205, 389, 689, 1565, 1625, 1781, 3865, 4105, 4549, 5989, 7421, 9161, 9685, 10225, 10685, 13025, 17509, 17965, 18329, 21349, 21701, 25801, 33161, 33169, 33529, 36749, 38581, 39709, 49325, 51649, 52429, 52721, 56785, 57065, 67205, 70801
Offset: 1

Views

Author

Lekraj Beedassy, Nov 06 2003

Keywords

Examples

			9161 is in the sequence because of the triple 5289^2 + 7480^2 = 9161^2 where we have 5289+7480=113^2.
Similarly, 205 belongs to the triple (133,156,205) and 133+156=17^2.
		

References

  • F. Rubin, "Squared" Pythagorean Triples, Solution to problem 2306, J. Recreational Mathematics, Vol. 29, No. 1, 1998, p. 73.

Crossrefs

Programs

  • Mathematica
    terms = 1000; jmax = 100; kmax = 200;
    Reap[Do[If[CoprimeQ[j, k], e = j^2 - j k + k^2/2; f = j k; If[e > f, Sow[e^2 + f^2]]], {j, 1, jmax}, {k, 2, kmax, 2}]][[2, 1]] // Union // Take[#, terms]& (* Jean-François Alcover, Mar 04 2020 *)

Formula

a(n)=e^2+f^2, where e>f, e=j^2 - jk + k^2/2 and f=jk for coprime pairs (j, k) with k even.

A088515 Values j of pairs (j,k) that generate A088319(n).

Original entry on oeis.org

1, 1, 5, 1, 7, 7, 1, 1, 9, 9, 3, 1, 11, 11, 3, 11, 1, 5, 13, 13, 1, 13, 3, 1, 15, 15, 5, 3, 15, 1, 5, 17, 17, 7, 17, 17, 1, 5, 7, 3, 19, 19, 19, 19, 5, 1, 19, 3, 21, 21, 7, 1, 21, 21, 7, 5, 23, 9, 23, 1, 23, 23, 3, 23, 7, 5, 9, 1, 23, 3, 25, 25, 7, 25, 25, 5, 25, 1, 7, 9, 27, 25, 27, 27, 5, 11, 1
Offset: 1

Views

Author

Lekraj Beedassy, Nov 14 2003

Keywords

Crossrefs

Programs

  • Mathematica
    terms = 1000; jmax = 100; kmax = 200;
    Reap[Do[If[CoprimeQ[j, k], e = j^2 - j k + k^2/2; f = j k; If[e > f, Sow[{e^2 + f^2, j, k}]]], {j, 1, jmax}, {k, 2, kmax, 2}]][[2, 1]] // Sort // #[[;; terms, 2]]& (* Jean-François Alcover, Mar 05 2020 *)

Extensions

Corrected and extended by Ray Chandler, Nov 16 2003

A088516 Values k of pairs (j,k) that generate A088319(n).

Original entry on oeis.org

4, 6, 2, 8, 2, 4, 10, 12, 4, 2, 14, 14, 4, 6, 16, 2, 16, 18, 6, 4, 18, 2, 20, 20, 8, 4, 22, 22, 2, 22, 24, 6, 8, 24, 4, 2, 24, 26, 26, 26, 8, 6, 10, 4, 28, 26, 2, 28, 8, 10, 30, 28, 4, 2, 32, 32, 10, 32, 8, 30, 12, 6, 32, 4, 34, 34, 34, 32, 2, 34, 12, 8, 36, 14, 6, 36, 4, 34, 38, 38, 10, 2
Offset: 1

Views

Author

Lekraj Beedassy, Nov 14 2003

Keywords

Crossrefs

Programs

  • Mathematica
    terms = 1000; jmax = 100; kmax = 200;
    Reap[Do[If[CoprimeQ[j, k], e = j^2 - j k + k^2/2; f = j k; If[e > f, Sow[{e^2 + f^2, j, k}]]], {j, 1, jmax}, {k, 2, kmax, 2}]][[2, 1]] // Sort // #[[;; terms, 3]]& (* Jean-François Alcover, Mar 05 2020 *)

Extensions

Corrected and extended by Ray Chandler, Nov 16 2003

A088546 Square root of sum of legs of primitive Pythagorean triangles having legs that add up to a square, sorted on hypotenuse.

Original entry on oeis.org

7, 17, 23, 31, 47, 41, 49, 71, 73, 79, 89, 97, 113, 103, 119, 119, 127, 137, 151, 161, 161, 167, 191, 199, 193, 217, 217, 233, 223, 241, 263, 271, 257, 239, 281, 287, 287, 313, 289, 329, 329, 343, 311, 353, 367, 337, 359, 383, 409, 391, 401, 391, 433, 439, 463
Offset: 1

Views

Author

Lekraj Beedassy, Nov 17 2003

Keywords

Comments

Numbers whose square is the sum of the legs of primitive Pythagorean triangles with hypotenuse A088319(n).

Examples

			31 is in the sequence because it is associated with the primitive Pythagorean triangle (400,561,689) where 400+561=31^2.
		

Crossrefs

Programs

  • Mathematica
    terms = 1000; jmax = 100; kmax = 200;
    Reap[Do[If[CoprimeQ[j, k], e = j^2 - j k + k^2/2; f = j k; If[e > f, Sow[{e^2 + f^2, Abs[j^2 - k^2/2]}]]], {j, 1, jmax}, {k, 2, kmax, 2}]][[2, 1]] // Sort // #[[;; terms, 2]]& (* Jean-François Alcover, Mar 05 2020 *)

Formula

a(n) = abs(j^2 - k^2/2), where j=A088515(n), k=A088516(n).
a(n) = sqrt(A089552(n)).

Extensions

More terms from Ray Chandler, Nov 16 2003

A089545 Values e of pairs (e,f) that generate A088319(n).

Original entry on oeis.org

5, 13, 17, 25, 37, 29, 41, 61, 53, 65, 65, 85, 85, 73, 89, 101, 113, 97, 109, 125, 145, 145, 149, 181, 137, 173, 157, 185, 197, 221, 193, 205, 185, 169, 229, 257, 265, 233, 205, 269, 241, 265, 221, 293, 277, 313, 325, 317, 305, 281, 289, 365, 365, 401, 337, 377
Offset: 1

Views

Author

Ray Chandler, Nov 16 2003

Keywords

Crossrefs

A089554 a(n)=(A088515(n)+1)/2.

Original entry on oeis.org

1, 1, 3, 1, 4, 4, 1, 1, 5, 5, 2, 1, 6, 6, 2, 6, 1, 3, 7, 7, 1, 7, 2, 1, 8, 8, 3, 2, 8, 1, 3, 9, 9, 4, 9, 9, 1, 3, 4, 2, 10, 10, 10, 10, 3, 1, 10, 2, 11, 11, 4, 1, 11, 11, 4, 3, 12, 5, 12, 1, 12, 12, 2, 12, 4, 3, 5, 1, 12, 2, 13, 13, 4, 13, 13, 3, 13, 1, 4, 5, 14, 13, 14, 14, 3, 6, 1, 2, 5, 4, 14, 6
Offset: 1

Views

Author

Ray Chandler, Nov 16 2003

Keywords

Crossrefs

A089558 a(n)=A089551(n)/2.

Original entry on oeis.org

2, 21, 35, 68, 161, 14, 155, 294, 306, 423, 483, 497, 902, 231, 984, 869, 776, 315, 1209, 1898, 1143, 1547, 2670, 1610, 1020, 3390, 2585, 3927, 2505, 2189, 4380, 5253, 3332, 84, 5474, 3791, 2892, 6695, 2093, 7449, 6764, 8607, 2945, 8246, 9590, 3731, 5453
Offset: 1

Views

Author

Ray Chandler, Nov 16 2003

Keywords

Crossrefs

A089546 Values f of pairs (e,f) that generate A088319(n).

Original entry on oeis.org

4, 6, 10, 8, 14, 28, 10, 12, 36, 18, 42, 14, 44, 66, 48, 22, 16, 90, 78, 52, 18, 26, 60, 20, 120, 60, 110, 66, 30, 22, 120, 102, 136, 168, 68, 34, 24, 130, 182, 78, 152, 114, 190, 76, 140, 26, 38, 84, 168, 210, 210, 28, 84, 42, 224, 160, 230, 288, 184, 30, 276, 138, 96, 92
Offset: 1

Views

Author

Ray Chandler, Nov 16 2003

Keywords

Crossrefs

A089551 Radius of inscribed circle within primitive Pythagorean triangles having legs that add up to a square, sorted on hypotenuse.

Original entry on oeis.org

4, 42, 70, 136, 322, 28, 310, 588, 612, 846, 966, 994, 1804, 462, 1968, 1738, 1552, 630, 2418, 3796, 2286, 3094, 5340, 3220, 2040, 6780, 5170, 7854, 5010, 4378, 8760, 10506, 6664, 168, 10948, 7582, 5784, 13390, 4186, 14898, 13528, 17214, 5890, 16492, 19180
Offset: 1

Views

Author

Ray Chandler, Nov 16 2003

Keywords

Crossrefs

A089547 Short leg of primitive Pythagorean triangles having legs that add up to a square, sorted on hypotenuse.

Original entry on oeis.org

9, 133, 189, 400, 1036, 57, 820, 1464, 1513, 2340, 2461, 2380, 5289, 973, 5617, 4444, 3616, 1309, 5797, 12921, 5220, 7540, 17880, 7240, 4369, 20760, 12549, 24420, 11820, 9724, 22849, 31621, 15729, 337, 31144, 17476, 12720, 37389, 8901, 41964, 34977
Offset: 1

Views

Author

Ray Chandler, Nov 16 2003

Keywords

Crossrefs

Showing 1-10 of 17 results. Next