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

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

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

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

A089552 Sum of legs of primitive Pythagorean triangles having legs that add up to a square, sorted on hypotenuse.

Original entry on oeis.org

49, 289, 529, 961, 2209, 1681, 2401, 5041, 5329, 6241, 7921, 9409, 12769, 10609, 14161, 14161, 16129, 18769, 22801, 25921, 25921, 27889, 36481, 39601, 37249, 47089, 47089, 54289, 49729, 58081, 69169, 73441, 66049, 57121, 78961, 82369
Offset: 1

Views

Author

Ray Chandler, Nov 16 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^2 - k^2/2)^2}]]], {j, 1, jmax}, {k, 2, kmax, 2}]][[2, 1]] // Sort // #[[;; terms, 2]]& (* Jean-François Alcover, Mar 05 2020 *)

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

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

A380072 Ordered hypotenuses of Pythagorean triangles having legs that add up to a square.

Original entry on oeis.org

35, 41, 140, 164, 205, 221, 315, 369, 389, 391, 560, 656, 689, 775, 820, 875, 884, 1025, 1189, 1260, 1476, 1556, 1564, 1565, 1625, 1715, 1739, 1781, 1845, 1855, 1989, 2009, 2240, 2624, 2756, 2835, 3100, 3280, 3321, 3500, 3501, 3519, 3536, 3865, 3869, 4100, 4105
Offset: 1

Views

Author

Felix Huber, Jan 18 2025

Keywords

Comments

Corresponding long legs in A380073, short legs in A380074.
Subsequence of A009000 and supersequence of A088319.

Examples

			35 is in the sequence because 21^2 + 28^2 = 35^2 and 21 + 28 = 7^2.
206125 is twice in the sequence because 31525^2 + 203700^2 = 206125^2 and 31525 + 203700 = 485^2 as well as 94588^2 + 183141^2 = 206125^2 and 94588 + 183141 = 527^2.
		

Crossrefs

Programs

  • Maple
    # Calculates the first 10001 terms
    A380072:=proc(M)
        local i,m,p,q,r,w,L;
        L:=[];
        m:=M^2+2*M+2;
        for p from 2 to M do
            for q to p-1 do
                if gcd(p,q)=1 and (is(p,even) or is(q,even)) then
                    r:=1;
                    for i in ifactors(p^2-q^2+2*p*q)[2] do
                        if is(i[2],odd) then
                            r:=r*i[1]
                        fi
                    od;
                    w:=r*(p^2+q^2);
                    if w<=m then
                        L:=[op(L),seq(i^2*w,i=1..floor(sqrt(m/w)))]
                    fi
                fi
            od
        od;
        return op(sort(L))
    end proc;
    A380072(4330);

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

Showing 1-10 of 17 results. Next