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 1-6 of 6 results.

A045617 Erroneous version of A034057.

Original entry on oeis.org

10, 5, 11, 2, 21, 7, 3, 8, 26, 199, 83, 17, 124, 51, 173, 10, 201, 67, 27, 149, 52, 126, 5, 18, 541, 127, 86, 53, 28, 69, 11, 40, 336, 54, 19, 70, 179, 29, 108, 41, 2, 71, 89, 6, 181, 12, 20, 42, 182, 1407, 381, 157, 91, 57, 43, 31, 134, 21, 92, 13, 58, 214, 44, 7, 32, 75
Offset: 1

Views

Author

Keywords

A095156 Least k such that 1/k begins with n after deleting the decimal point and the zeros following the decimal point.

Original entry on oeis.org

6, 4, 3, 21, 2, 15, 13, 12, 11, 10, 9, 8, 72, 7, 63, 6, 56, 53, 51, 5, 46, 44, 42, 41, 4, 38, 36, 35, 34, 33, 32, 31, 3, 29, 28, 271, 27, 26, 251, 25, 24, 233, 23, 223, 22, 213, 21, 205, 201, 2, 193, 19, 186, 182, 18, 176, 173, 17, 167, 164, 162, 16, 157, 154, 152, 15, 148
Offset: 1

Views

Author

Amarnath Murthy, May 31 2004

Keywords

Examples

			a(1) =  6 -> 1/6 = 0.{1}666666...
a(2) =  4 -> 1/4 = 0.{2}500000...
a(3) =  3 -> 1/3 = 0.{3}333333...
a(4) = 21 -> 1/4 = 0.0{4}76190...
a(5) =  2 -> 1/2 = 0.{5}000000...
a(7) = 13 as 1/13 = 0.0767... and on deleting the decimal point one gets 0714... = 714... which begins with 7.
a(8) = 12 though 1/125 = 0.8. 1/12 = 0.083...

Links

Crossrefs

Cf. A034057.

Programs

  • Mathematica
    Do[k = 1; l = {}; d = IntegerDigits[n]; While[FromDigits[l] != n, k++; f = First[RealDigits[N[1/k, 10]]]; If[Length[f] > Length[d], l = Take[f, Length[d]], l = f]]; Print[k], {n, 1, 100}] (* Ryan Propper, Aug 10 2005 *)

Extensions

Corrected and extended by Ryan Propper, Aug 10 2005
Edited by N. J. A. Sloane, May 07 2007

A034067 Decimal part of a(n)^(1/2) starts with n so that a(n)

Original entry on oeis.org

26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 199, 293, 405, 490, 583, 633, 738, 794, 852, 912, 974, 1038, 1104, 1172, 1173, 1243, 1315, 1316, 1390, 1391, 1392, 1468, 1469, 1547, 1548, 1549, 1629, 1630, 1631, 1632, 1714, 1715, 1716, 1717, 1718, 1888, 1889, 1890
Offset: 0

Views

Author

Patrick De Geest, Sep 15 1998

Keywords

Examples

			a(10)=199 -> 199^(1/2)=14.{10}67359...: a(11)=293 -> 293^(1/2)=17.{11}72427... and a(10)=199 < a(11)=293.

Crossrefs

Cf. A034057, A034077.

A034077 Decimal part of n-th root of a(n) starts with digit 0.

Original entry on oeis.org

26, 9, 17, 33, 65, 129, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2
Offset: 2

Views

Author

Patrick De Geest, Sep 15 1998

Keywords

Examples

			a(2)=26 -> 26^(1/2)=5.{0}990195...

Crossrefs

Cf. A034057, A034067.

A099406 Decimal part of 1/a(n) starts with the n-th prime (leading zeros excluded).

Original entry on oeis.org

4, 3, 2, 13, 9, 72, 56, 51, 42, 34, 32, 27, 24, 23, 21, 186, 167, 162, 148, 14, 136, 126, 12, 112, 103, 99, 97, 93, 91, 88, 782, 76, 725, 715, 67, 66, 633, 61, 596, 575, 556, 55, 521, 516, 506, 501, 472, 447, 44, 435, 428, 417, 414, 397, 388, 38, 371, 368, 36, 355, 353
Offset: 1

Views

Author

Gil Broussard, Nov 17 2004

Keywords

Examples

			a(1)= 4 -> 1/4 =0.{2}500000...
a(2)= 3 -> 1/3 =0.{3}333333...
a(3)= 2 -> 1/2 =0.{5}000000...
a(4)=13 -> 1/13=0.0{7}69230...
a(100)=1846 -> 1/1846=0.000{541}712 and 541 is the 100th prime.

Crossrefs

Cf. A034057, A052039.

Formula

a(n) = A052039(prime(n)). - Michel Marcus, Jan 08 2025

A326818 a(n) is the smallest k such that the first significant digits of 1/k coincide with n.

Original entry on oeis.org

1, 4, 3, 21, 2, 15, 13, 12, 11, 1, 9, 8, 72, 7, 63, 6, 56, 53, 51, 5, 46, 44, 42, 41, 4, 38, 36, 35, 34, 33, 32, 31, 3, 29, 28, 271, 27, 26, 251, 25, 24, 233, 23, 223, 22, 213, 21, 205, 201, 2, 193, 19, 186, 182, 18, 176, 173, 17, 167, 164, 162, 16, 157, 154, 152
Offset: 1

Views

Author

Giovanni Resta, Oct 20 2019

Keywords

Comments

This sequence differs from A052039 in how it treats reciprocals with terminating representation, i.e., the values 1/k for integers k whose prime factors are 2 and/or 5. For example, here we assume 1/5 = 0.2000... which leads to a(20) = 5, while in A052039 we consider 1/5 = 0.2 (without trailing zeros), which leads to A052039(20) = 48 instead.

Examples

			a(123) = 81 because 1/81 = 0.0(123)4... and 81 is the smallest number with this property.

Crossrefs

Cf. A052039, A034057.

Programs

  • Mathematica
    a[n_] := Block[{d = IntegerDigits[n], m, k = 1}, m = Length[d]; While[ RealDigits[1/k, 10, m][[1]] != d, k++]; k]; Array[a, 65]
Showing 1-6 of 6 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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