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.

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A097225 Numbers n that are the hypotenuse of exactly 10 distinct integer-sided right triangles, i.e., n^2 can be written as a sum of two squares in 10 ways.

Original entry on oeis.org

1625, 2125, 3250, 3625, 4250, 4625, 4875, 5125, 6375, 6500, 6625, 7250, 7625, 8500, 9125, 9250, 9750, 10250, 10875, 10985, 11125, 11375, 12125, 12625, 12750, 13000, 13250, 13625, 13875, 14125, 14500, 14625, 14875, 15250, 15375, 17000, 17125
Offset: 1

Views

Author

James R. Buddenhagen, Sep 17 2004

Keywords

Comments

If m is a term, then 2*m and p*m are terms where p is any prime of the form 4k+3. - Ray Chandler, Dec 30 2019

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097282 (40), A097626 (67).

Programs

  • Mathematica
    r[n_] := Reduce[0 < x <= y && n^2 == x^2 + y^2, {x, y}, Integers]; Reap[For[n = 5, n <= 20000, n++, rn = r[n]; If[rn =!= False, If[Length[r[n]] == 10, Print[n]; Sow[n]]]]][[2, 1]] (* Jean-François Alcover, Nov 15 2016 *)

A097238 Numbers j that are the hypotenuse of exactly 16 distinct integer-sided right triangles, i.e., j^2 can be written as a sum of two squares in 16 ways.

Original entry on oeis.org

40625, 53125, 81250, 90625, 106250, 115625, 121875, 128125, 159375, 162500, 165625, 181250, 190625, 212500, 228125, 231250, 243750, 256250, 271875, 278125, 284375, 303125, 315625, 318750, 325000, 331250, 340625, 346875, 353125, 362500
Offset: 1

Views

Author

James R. Buddenhagen, Sep 17 2004

Keywords

Comments

If m is a term, then 2*m and p*m are terms where p is any prime of the form 4k+3. - Ray Chandler, Dec 30 2019

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097282 (40), A097626 (67).

Extensions

More terms from Ray Chandler, Sep 18 2004
Offset corrected by Michel Marcus, Aug 04 2017

A097239 Numbers n that are the hypotenuse of exactly 17 distinct integer-sided right triangles, i.e., n^2 can be written as a sum of two squares in 17 ways.

Original entry on oeis.org

21125, 36125, 42250, 54925, 63375, 72250, 84500, 105125, 108375, 109850, 122825, 126750, 144500, 147875, 164775, 169000, 171125, 190125, 210125, 210250, 216750, 219700, 232375, 245650, 252875, 253500, 289000, 295750, 315375, 325125, 329550
Offset: 1

Views

Author

James R. Buddenhagen, Sep 17 2004

Keywords

Comments

If m is a term, then 2*m and p*m are terms where p is any prime of the form 4k+3. - Ray Chandler, Dec 30 2019

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097238 (16), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097282 (40), A097626 (67).

Extensions

More terms from Ray Chandler, Sep 18 2004
Offset corrected by Michel Marcus, Aug 04 2017

A097244 Numbers n that are the hypotenuse of exactly 31 distinct integer-sided right triangles, i.e., n^2 can be written as a sum of two squares in 31 ways.

Original entry on oeis.org

27625, 47125, 55250, 60125, 61625, 66625, 78625, 82875, 86125, 87125, 94250, 99125, 110500, 112625, 118625, 120250, 123250, 129625, 133250, 134125, 141375, 144625, 148625, 155125, 157250, 157625, 164125, 165750, 172250, 174250, 177125
Offset: 1

Views

Author

James R. Buddenhagen, Sep 17 2004

Keywords

Comments

If m is a term, then 2*m and p*m are terms where p is any prime of the form 4k+3. - Ray Chandler, Dec 30 2019

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097245 (37), A097282 (40), A097626 (67).

A097245 Numbers k that are the hypotenuse of exactly 37 distinct integer-sided right triangles, i.e., k^2 can be written as a sum of two squares in 37 ways.

Original entry on oeis.org

71825, 93925, 122525, 143650, 156325, 173225, 187850, 209525, 215475, 223925, 244205, 245050, 257725, 267325, 273325, 281775, 287300, 296225, 308425, 312650, 346450, 357425, 367575, 375700, 376025, 382925, 409825, 419050, 426725, 430950
Offset: 1

Views

Author

James R. Buddenhagen, Sep 17 2004

Keywords

Comments

If m is a term, then 2*m and p*m are terms where p is any prime of the form 4k+3. - Ray Chandler, Dec 30 2019

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097282 (40), A097626 (67).

Extensions

More terms from Ray Chandler, Sep 18 2004

A097282 Numbers k that are the hypotenuse of exactly 40 distinct integer-sided right triangles, i.e., k^2 can be written as a sum of two squares in 40 ways.

Original entry on oeis.org

32045, 40885, 45305, 58565, 64090, 67405, 69745, 77285, 80665, 81770, 90610, 91205, 96135, 98345, 98605, 99905, 101065, 107185, 111605, 114985, 117130, 120445, 122655, 124865, 127465, 128180, 128945, 130645, 134810, 135915, 137605
Offset: 1

Views

Author

James R. Buddenhagen, Sep 17 2004

Keywords

Comments

k^2 is always the sum of k^2 and 0^2, but no real triangle can have a zero-length side. Thus, the Mathematica program below searches for length 41 and implicitly drops the zero-squared-plus-n-squared solution. - Harvey P. Dale, Dec 09 2010
If m is a term, then 2*m and p*m are terms where p is any prime of the form 4j+3. - Ray Chandler, Dec 30 2019

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097626 (67).

Programs

  • Mathematica
    Select[Range[150000],Length[PowersRepresentations[#^2,2,2]]==41&] (* Harvey P. Dale, Dec 09 2010 *)

A097626 Numbers k that are the hypotenuse of exactly 67 distinct integer-sided right triangles, i.e., k^2 can be written as a sum of two squares in 67 ways.

Original entry on oeis.org

160225, 204425, 226525, 292825, 320450, 337025, 348725, 386425, 403325, 408850, 416585, 453050, 456025, 480675, 491725, 493025, 499525, 505325, 531505, 535925, 544765, 558025, 574925, 585650, 588965, 602225, 613275, 624325, 637325, 640900
Offset: 1

Views

Author

James R. Buddenhagen, Sep 20 2004

Keywords

Comments

If m is a term, then 2*m and p*m are terms where p is any prime of the form 4j+3. - Chai Wah Wu, Feb 29 2016

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097282 (40).

Programs

  • Mathematica
    r[a_]:={b, c}/.{ToRules[Reduce[0Vincenzo Librandi, Mar 01 2016 *)

Extensions

More terms from Ray Chandler, Sep 21 2004

A290499 Hypotenuses for which there exist exactly 8 distinct integer triangles.

Original entry on oeis.org

390625, 781250, 1171875, 1562500, 2343750, 2734375, 3125000, 3515625, 4296875, 4687500, 5468750, 6250000, 7031250, 7421875, 8203125, 8593750, 8984375, 9375000, 10546875, 10937500, 12109375, 12500000, 12890625, 14062500, 14843750, 16406250, 16796875, 17187500
Offset: 1

Views

Author

Hamdi Sahloul, Aug 04 2017

Keywords

Comments

Numbers whose square is decomposable in 8 different ways into the sum of two nonzero squares: these are those with only one prime divisor of the form 4k+1 with multiplicity eight.

Examples

			a(1) = 390625 = 5^8, a(5) = 2343750 = 2*3*5^8, a(101) = 75000000 = 2^6*3*5^8.
		

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097282 (40), A097626 (67).

Programs

  • Mathematica
    r[a_]:={b, c}/.{ToRules[Reduce[0Vincenzo Librandi, Mar 01 2016 *)

Formula

Terms are obtained by the product A004144(k)*A002144(p)^8 for k, p > 0 ordered by increasing values.

A290500 Hypotenuses for which there exist exactly 9 distinct integer triangles.

Original entry on oeis.org

1953125, 3906250, 5859375, 7812500, 11718750, 13671875, 15625000, 17578125, 21484375, 23437500, 27343750, 31250000, 35156250, 37109375, 41015625, 42968750, 44921875, 46875000, 52734375, 54687500, 60546875, 62500000, 64453125, 70312500, 74218750, 82031250
Offset: 1

Views

Author

Hamdi Sahloul, Aug 04 2017

Keywords

Comments

Numbers whose square is decomposable in 9 different ways into the sum of two nonzero squares: these are those with only one prime divisor of the form 4k+1 with multiplicity nine.

Examples

			a(1) = 1953125 = 5^9, a(5) = 11718750 = 2*3*5^9, a(101) = 375000000 = 2^6*3*5^9.
		

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290502 (14), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097282 (40), A097626 (67).

Programs

  • Mathematica
    r[a_]:={b, c}/.{ToRules[Reduce[0Vincenzo Librandi, Mar 01 2016 *)

Formula

Terms are obtained by the product A004144(k)*A002144(p)^9 for k, p > 0 ordered by increasing values.

A290502 Hypotenuses for which there exist exactly 14 distinct integer triangles.

Original entry on oeis.org

6103515625, 12207031250, 18310546875, 24414062500, 36621093750, 42724609375, 48828125000, 54931640625, 67138671875, 73242187500, 85449218750, 97656250000, 109863281250, 115966796875, 128173828125, 134277343750, 140380859375, 146484375000, 164794921875
Offset: 1

Views

Author

Hamdi Sahloul, Aug 04 2017

Keywords

Comments

Numbers whose square is decomposable in 14 different ways into the sum of two nonzero squares: these are those with only one prime divisor of the form 4k+1 with multiplicity fourteen.

Examples

			a(1) = 6103515625 = 5^14, a(5) = 36621093750 = 2*3*5^14, a(101) = 1171875000000 = 2^6*3*5^14.
		

Crossrefs

Cf. A004144 (0), A084645 (1), A084646 (2), A084647 (3), A084648 (4), A084649 (5), A097219 (6), A097101 (7), A290499 (8), A290500 (9), A097225 (10), A290501 (11), A097226 (12), A097102 (13), A290503 (15), A097238 (16), A097239 (17), A290504 (18), A290505 (19), A097103 (22), A097244 (31), A097245 (37), A097282 (40), A097626 (67).

Programs

  • Mathematica
    r[a_]:={b, c}/.{ToRules[Reduce[0Vincenzo Librandi, Mar 01 2016 *)

Formula

Terms are obtained by the product A004144(k)*A002144(p)^14 for k, p > 0 ordered by increasing values.
Previous Showing 11-20 of 23 results. Next