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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A115535 Numbers k such that the concatenation of k with 4*k gives a square.

Original entry on oeis.org

25721, 28836, 32129, 35600, 39249, 43076, 47081, 51264, 55625, 60164, 64881, 69776, 74849, 80100, 85529, 91136, 96921, 102884, 109025, 115344, 121841, 128516, 135369, 142400, 149609, 156996, 164561, 172304, 180225, 188324, 196601, 205056
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Comments

Not the same as P(n) = 89*n^2 + 2848*n + 22784: P(n) = a(n) for a < 37, but a(37) = 3698225. - Charles R Greathouse IV, Jul 28 2010

Examples

			25721_102884 = 160378^2.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

Programs

  • Mathematica
    Select[Range[250000],IntegerQ[Sqrt[#*10^IntegerLength[4*#]+4*#]]&] (* Harvey P. Dale, Jan 04 2019 *)

A115536 Numbers k such that the square of k is the concatenation of two numbers m and 4*m.

Original entry on oeis.org

160378, 169812, 179246, 188680, 198114, 207548, 216982, 226416, 235850, 245284, 254718, 264152, 273586, 283020, 292454, 301888, 311322, 320756, 330190, 339624, 349058, 358492, 367926, 377360, 386794, 396228, 405662
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			160378^2 = 25721_102884.

Links

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

A115537 Numbers k such that the concatenation of 4*k with k gives a square.

Original entry on oeis.org

17728531856, 27700831025, 39889196676, 54293628809, 70914127424, 89750692521, 32653061224489796, 73469387755102041, 1245674740484429065743944636678200692041522491349481
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			70914127424_17728531856 = 84210526316^2.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

A115538 Numbers k such that k^2 is the concatenation of two numbers 4*m and m.

Original entry on oeis.org

84210526316, 105263157895, 126315789474, 147368421053, 168421052632, 189473684211, 114285714285714286, 171428571428571429, 7058823529411764705882352941176470588235294117647059
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			84210526316^2 = 70914127424_17728531856.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

Extensions

Definition modified by Georg Fischer, Jul 26 2019

A115539 Numbers k such that the concatenation of k with 5*k gives a square.

Original entry on oeis.org

2040816326530612245, 8163265306122448980, 18367346938775510205, 265008112493239588967009194159005, 346133044889129259058950784207680, 438074634937804218496484586262845, 540832882639264467279610600324500
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			2040816326530612245_10204081632653061225 = 14285714285714285715^2.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

A115540 Numbers k such that k^2 is the concatenation of two numbers m and 5*m.

Original entry on oeis.org

14285714285714285715, 28571428571428571430, 42857142857142857145, 1627906976744186046511627906976745, 1860465116279069767441860465116280
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			14285714285714285715^2 = 2040816326530612245_10204081632653061225.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

A115541 Numbers k such that the concatenation of 5*k with k gives a square.

Original entry on oeis.org

1020408163265306122449, 4081632653061224489796, 9183673469387755102041, 106678449690695619239994950132559020325716449943188991289, 123721752304002019946976391869713420022724403484408534276
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			5102040816326530612245_1020408163265306122449 = 7142857142857142857143^2.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

A115542 Numbers k such that k^2 is the concatenation of two numbers 5*m and m.

Original entry on oeis.org

7142857142857142857143, 14285714285714285714286, 21428571428571428571429, 730337078651685393258426966292134831460674157303370786517
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			7142857142857142857143^2 = 5102040816326530612245_1020408163265306122449.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

Extensions

Definition modified by Georg Fischer, Jul 26 2019

A115543 Numbers k such that the concatenation of k with 6*k gives a square.

Original entry on oeis.org

1, 20408163265306122448979591836734694, 81632653061224489795918367346938776, 20408163265306122448979591836734693877551020408163265306122448979591836734694
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			1_6 = 4^2.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.

A115544 Numbers k such that k^2 is the concatenation of two numbers m and 6*m.

Original entry on oeis.org

4, 142857142857142857142857142857142858, 285714285714285714285714285714285716, 142857142857142857142857142857142857142857142857142857142857142857142857142858
Offset: 1

Views

Author

Giovanni Resta, Jan 25 2006

Keywords

Examples

			4^2 = 1_6.

Crossrefs

Cf. A102567, A106497, A115527 - A115556.
Previous Showing 11-20 of 30 results. Next

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