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 1-5 of 5 results.

A217399 Numbers starting with 6.

Original entry on oeis.org

6, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 600, 601, 602, 603, 604, 605, 606, 607, 608, 609, 610, 611, 612, 613, 614, 615, 616, 617, 618, 619, 620, 621, 622, 623, 624, 625, 626, 627, 628, 629, 630, 631, 632, 633, 634, 635, 636, 637, 638, 639, 640, 641, 642
Offset: 1

Views

Author

Jeremy Gardiner, Oct 02 2012

Keywords

Comments

The lower and upper asymptotic densities of this sequence are 1/54 and 10/63, respectively. - Amiram Eldar, Feb 27 2021

Links

Crossrefs

Cf. A000870, A011536.
Subsequences include: A045712, A077331, A077682, A106416, A106426.
Cf. A131835, A217394, A217395, A217397, A217398, A217400, A217401, A217402.

Programs

  • GAP
    Flat(List([0..2],n->List([0..10^n-1],k->6*10^n+k))); # Muniru A Asiru, Nov 21 2018
  • Magma
    [n: n in [1..1600] | Intseq(n)[#Intseq(n)] eq 6]; // Vincenzo Librandi, Nov 24 2018
  • Maple
    seq(seq(6*10^n+k, k=0..10^n-1),n=0..3); # Robert Israel, May 08 2017
  • Mathematica
    Select[Range[1000], IntegerDigits[#][[1]] == 6 &] (* T. D. Noe, Oct 02 2012 *)
  • PARI
    isok(n) = digits(n)[1] == 6; \\ Michel Marcus, May 08 2017
  • Python
    def A217399(n): return n+(53*10**(len(str(9*n-8))-1))//9 # Chai Wah Wu, Dec 07 2024

Formula

a(n) = n + (53*10^floor(log_10(9*n-8))-8)/9. - Alan Michael Gómez Calderón, May 17 2023

A217400 Numbers starting with 7.

Original entry on oeis.org

7, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 700, 701, 702, 703, 704, 705, 706, 707, 708, 709, 710, 711, 712, 713, 714, 715, 716, 717, 718, 719, 720, 721, 722, 723, 724, 725, 726, 727, 728, 729, 730, 731, 732, 733, 734, 735, 736, 737, 738, 739, 740, 741, 742
Offset: 1

Views

Author

Jeremy Gardiner, Oct 02 2012

Keywords

Comments

The lower and upper asymptotic densities of this sequence are 1/63 and 5/36, respectively. - Amiram Eldar, Feb 27 2021

Links

Crossrefs

Cf. A000870, A011537.
Subsequences include: A045713, A077332, A077683, A106417, A106427.
Cf. A131835, A217394, A217395, A217397, A217398, A217399, A217401, A217402.

Programs

  • Mathematica
    Select[Range[1000], IntegerDigits[#][[1]] == 7 &] (* T. D. Noe, Oct 02 2012 *)
  • Python
    def A217400(n): return n+(62*10**(len(str(9*n-8))-1))//9 # Chai Wah Wu, Dec 07 2024

Formula

a(n) = n + (62*10^floor(log_10(9*n-8))-8)/9. - Alan Michael Gómez Calderón, May 17 2023

A000867 Numbers beginning with letter 'f' in English.

Original entry on oeis.org

4, 5, 14, 15, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432
Offset: 1

Views

Author

N. J. A. Sloane

Keywords

Links

Crossrefs

Subsequence of A125299.
Cf. A000865, A000870, A000873, A000981, A006092.

Programs

  • Mathematica
    Select[Range[1000], First[Characters[IntegerName[#,"Words"]]]=="f"&] (* James C. McMahon, Dec 11 2023 *)

Extensions

More terms from John Cerkan, Feb 11 2017

A000873 Numbers beginning with letter 'e' in English.

Original entry on oeis.org

8, 11, 18, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 800, 801, 802, 803, 804, 805, 806, 807, 808, 809, 810, 811, 812, 813, 814, 815, 816, 817, 818, 819, 820, 821, 822, 823, 824, 825, 826, 827, 828, 829
Offset: 1

Views

Author

N. J. A. Sloane

Keywords

Links

Crossrefs

Subsequence of A000852.
Cf. A000865, A000867, A000870, A000981, A006092.

Programs

  • Mathematica
    Select[Range[10^3], Function[d, Or[And[Mod[IntegerLength@ #, 3] == 2, MemberQ[{11, 18}, FromDigits@ Take[d, 2]]], First@ d == 8]]@ IntegerDigits@ # &] (* Michael De Vlieger, Feb 13 2017 *)

Extensions

Corrected by Sam Alexander (pink2001x(AT)hotmail.com)
Edited by John Cerkan, Feb 13 2017

A000981 Numbers beginning with letter 'n' in English.

Original entry on oeis.org

9, 19, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 900, 901, 902, 903, 904, 905, 906, 907, 908, 909, 910, 911, 912, 913, 914, 915, 916, 917, 918, 919, 920, 921, 922, 923, 924, 925, 926, 927, 928, 929, 930
Offset: 1

Views

Author

N. J. A. Sloane

Keywords

Links

Crossrefs

Subsequence of A125299.
Cf. A000865, A000867, A000870, A000873, A006092.

Programs

  • Mathematica
    Select[Range[10^3], Function[d, Or[And[Mod[IntegerLength@ #, 3] == 2, FromDigits@ Take[d, 2] == 19], First@ d == 9]]@ IntegerDigits@ # &] (* Michael De Vlieger, Feb 13 2017 *)

Extensions

Edited by John Cerkan, Feb 13 2017
Showing 1-5 of 5 results.

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

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