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.

Previous Showing 11-19 of 19 results.

A292202 The n-th iteration of A062028 starting with n.

Original entry on oeis.org

2, 8, 15, 28, 25, 33, 59, 77, 90, 79, 109, 111, 134, 137, 129, 148, 184, 189, 218, 197, 204, 226, 250, 231, 284, 284, 297, 313, 325, 309, 341, 398, 354, 418, 418, 414, 488, 440, 438, 478, 529, 465, 545, 554, 531, 628, 658, 561, 620, 677, 624, 697, 697, 657, 785, 818, 735, 865, 835, 762, 851, 851
Offset: 1

Views

Author

Peter Weiss, Sep 11 2017

Keywords

Comments

a(n) == n*2^n (mod 9). This has a period of 18. - Robert Israel, Sep 11 2017

Examples

			n=5: 5+5=10, 10+1+0=11, 11+1+1=13, 13+1+3=17, 17+1+7=25. After 5 iterations you get 25, so a(5)=25.
		

Crossrefs

Programs

  • Maple
    A062028:= proc(t) option remember; t + convert(convert(t,base,10),`+`):end proc:
    seq((A062028@@n)(n), n=1..100); # Robert Israel, Sep 11 2017
  • Mathematica
    Table[Nest[# + Total@ IntegerDigits@ # &, n, n], {n, 62}] (* Michael De Vlieger, Sep 11 2017 *)
  • PARI
    a(n) = my(x=n); for (k=1, n, x += sumdigits(x)); x; \\ Michel Marcus, Sep 12 2017

A036227 a(1) = 20; a(n+1) = a(n) + sum of decimal digits of a(n).

Original entry on oeis.org

20, 22, 26, 34, 41, 46, 56, 67, 80, 88, 104, 109, 119, 130, 134, 142, 149, 163, 173, 184, 197, 214, 221, 226, 236, 247, 260, 268, 284, 298, 317, 328, 341, 349, 365, 379, 398, 418, 431, 439, 455, 469, 488, 508, 521, 529, 545, 559, 578, 598, 620, 628, 644, 658
Offset: 1

Views

Author

Miklos SZABO (mike(AT)ludens.elte.hu)

Keywords

Comments

elements >= 109 can be found in A007618.

Crossrefs

Programs

  • Mathematica
    NestList[#+Total[IntegerDigits[#]]&,20,60] (* Harvey P. Dale, May 11 2014 *)

Extensions

Edited by Charles R Greathouse IV, Aug 02 2010

A036233 Inverse Colombian function.

Original entry on oeis.org

1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 5, 3, 5, 7, 3, 1, 5, 9, 7, 20, 3, 20, 1, 3, 5, 20, 9, 1, 7, 3, 31, 5, 3, 20, 31, 9, 5, 1, 3, 7, 20, 42, 31, 7, 9, 20, 5, 42, 1, 31, 3, 7, 53, 9, 31, 20, 3, 5, 7, 42, 53, 1, 9, 64, 31, 42, 20, 53, 3, 1, 5, 9, 7, 64, 75, 31, 1, 42, 5, 20, 9, 53, 7, 3, 64, 86, 75, 20
Offset: 1

Views

Author

Miklos SZABO (mike(AT)ludens.elte.hu)

Keywords

Comments

a(n) is the smallest x with n in the digit summing sequence starting with x.
Contains only self-numbers, see A003052.

Crossrefs

A151942 Table of Self / Colombian numbers and their descendents.

Original entry on oeis.org

1, 2, 3, 4, 6, 5, 8, 12, 10, 7, 16, 15, 11, 14, 9, 23, 21, 13, 19, 18, 20, 28, 24, 17, 29, 27, 22, 31, 38, 30, 25, 40, 36, 26, 35, 42, 49, 33, 32, 44, 45, 34, 43, 48, 53, 62, 39, 37, 52, 54, 41, 50, 60, 61, 64, 70, 51, 47, 59, 63, 46, 55, 66, 68, 74, 75, 77, 57, 58, 73, 72, 56
Offset: 1

Views

Author

Carl R. White, Jul 13 2009

Keywords

Comments

Initially resembles a permutation of the integers, but this is not the case. 101 is the first number to appear twice, descending from both 91 and 100: 91 + 9+1 = 100 + 1+0+0 = 101

Crossrefs

First column of table is the Self numbers: A003052; First through eighth rows are A004207, A016052, A007618, A006507, A016096, A036227, A036228 respectively.

Formula

T(r,0) are those numbers not of form n + sum of digits of n (Self numbers)
T(r,c) = T(r,c-1) + sum of digits of T(r,c-1)

A292512 Sequence A: Start with n, add the sum of digits of n (A062028) and repeat. Sequence B: Start with n, add the sum of base-100 digits of n and repeat. a(n) is the smallest common number > n.

Original entry on oeis.org

2, 4, 6, 8, 10, 12, 14, 16, 18, 221, 341, 24, 109, 218, 30, 1171, 173, 36, 406, 80, 84, 88, 851, 96, 163, 104, 54, 218, 346, 120, 628, 1171, 231, 173, 181, 72, 197, 406, 213, 538, 260, 237, 1003, 1705, 90, 184, 719, 1041, 1015, 365, 111, 320, 127, 117, 418, 488, 114, 1487, 137, 120, 122, 199, 126, 1171, 298, 231, 134, 677
Offset: 1

Views

Author

Peter Weiss, Sep 18 2017

Keywords

Comments

If you start with n=1 and take a third sequence C (n + sum of base-1000 digits of n), the first common numbers of the three sequences are 2, 4, 8, 16 and 1027975.
The common numbers for the first ten primes are:
2 -> 4, 8, 16, 1027975, ...
3 -> 24, 96, 60342, ...
5 -> 10, 469534, ...
7 -> 14, 131558, ...
11 -> 923428, ...
13 -> 668495, ...
17 -> 81820, ...
19 -> 2061797, ...
23 -> 2227118, ...
29 -> 12278, ...

Examples

			n=10: Sequence A: 10, 11, 13, 17, 25, 32, 37, 47, 58, 71, 79, 95, 109, 119, 130, 134, 142, 149, 163, 173, 184, 197, 214, 221, ...
Sequence B: 10, 20, 40, 80, 160, 221, ...
-> 221 is the first common number > 10, so a(n)=221.
		

Crossrefs

Programs

  • Mathematica
    With[{m = 10^3}, Table[With[{A = Rest@ NestList[# + Total@ IntegerDigits@ # &, n, m]}, NestWhile[# + Total@ IntegerDigits[#, 100] &, n, FreeQ[A, #] &, 1, m]], {n, 68}]] (* Michael De Vlieger, Sep 23 2017 *)
  • PARI
    a(n) = my (A=n + sumdigits(n), B=n + sumdigits(n,100)); while (1, if (A==B, return (A), ARémy Sigrist, Sep 23 2017

A036230 a(n+1) = a(n) + sum of digits of a(n) starting with 110.

Original entry on oeis.org

110, 112, 116, 124, 131, 136, 146, 157, 170, 178, 194, 208, 218, 229, 242, 250, 257, 271, 281, 292, 305, 313, 320, 325, 335, 346, 359, 376, 392, 406, 416, 427, 440, 448, 464, 478, 497, 517, 530, 538, 554, 568, 587, 607, 620, 628, 644, 658, 677, 697, 719
Offset: 1

Views

Author

Miklos SZABO (mike(AT)ludens.elte.hu)

Keywords

Comments

Elements >= 218 can be found in A004207.

Crossrefs

Programs

  • Mathematica
    NestList[#+Total[IntegerDigits[#]]&,110,50] (* Harvey P. Dale, Oct 01 2017 *)

A036231 a(n+1) = a(n) + sum of digits of a(n) starting with 121.

Original entry on oeis.org

121, 125, 133, 140, 145, 155, 166, 179, 196, 212, 217, 227, 238, 251, 259, 275, 289, 308, 319, 332, 340, 347, 361, 371, 382, 395, 412, 419, 433, 443, 454, 467, 484, 500, 505, 515, 526, 539, 556, 572, 586, 605, 616, 629, 646, 662, 676, 695, 715, 728, 745
Offset: 1

Views

Author

Miklos SZABO (mike(AT)ludens.elte.hu)

Keywords

Comments

Elements >= 1003 can be found in A004207.

Crossrefs

A036232 a(n+1) = a(n) + sum of digits of a(n) starting with 211.

Original entry on oeis.org

211, 215, 223, 230, 235, 245, 256, 269, 286, 302, 307, 317, 328, 341, 349, 365, 379, 398, 418, 431, 439, 455, 469, 488, 508, 521, 529, 545, 559, 578, 598, 620, 628, 644, 658, 677, 697, 719, 736, 752, 766, 785, 805, 818, 835, 851, 865, 884, 904, 917, 934
Offset: 1

Views

Author

Miklos SZABO (mike(AT)ludens.elte.hu)

Keywords

Comments

Elements >= 317 can be found in A007618.

Crossrefs

Programs

  • Mathematica
    NestList[#+Total[IntegerDigits[#]]&,211,50] (* Harvey P. Dale, Jul 16 2020 *)

A362435 a(1) = 18; thereafter a(n) = a(n-1) + difference between first two digits of a(n-1).

Original entry on oeis.org

18, 25, 28, 34, 35, 37, 41, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44
Offset: 1

Views

Author

N. J. A. Sloane, Apr 21 2023

Keywords

Comments

44 is a fixed point.

References

  • GCHQ, The GCHQ Puzzle Book, Penguin, 2016. See page 36.

Crossrefs

Formula

G.f.: x*(18 + 7*x + 3*x^2 + 6*x^3 + x^4 + 2*x^5 + 4*x^6 + 3*x^7)/(1 - x). - Elmo R. Oliveira, Aug 03 2024
Previous Showing 11-19 of 19 results.