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 1-9 of 9 results.

A118515 Records in A118514.

Original entry on oeis.org

1, 3, 9, 10, 15, 16, 17, 64, 5317, 5324, 5325, 5326, 5327, 5332, 5333, 10268, 512105, 512112, 512113, 512114, 512115, 512120, 512121, 1007106, 51026173, 51026180, 51026181, 51026182, 51026183, 51026188, 51026189, 100526174
Offset: 1

Views

Author

N. J. A. Sloane, May 06 2006

Keywords

Crossrefs

Programs

  • C
    See Links section.
    
  • Python
    # See linked program in A118514.

Extensions

a(10) to a(25) from Klaus Brockhaus, Jun 12 2006
a(26) to a(32) from Rémy Sigrist, Aug 13 2022

A118516 Where records occur in A118514.

Original entry on oeis.org

1, 2, 12, 15, 25, 32, 102, 105, 111, 295, 392, 1002, 1918, 2187, 5812, 10009, 10011, 29995, 39992, 100002, 199918, 219987, 589912, 1000009, 1000011, 2999995, 3999992, 10000002, 19999918, 21999987, 58999912, 100000009
Offset: 1

Views

Author

N. J. A. Sloane, May 06 2006

Keywords

Comments

All terms so far enter the cycle of length 81, cf. A117521. - Klaus Brockhaus, Jun 12 2006

Crossrefs

Programs

  • C
    See Links section.
    
  • Python
    # See linked program in A118514.

Extensions

a(10) to a(25) from Klaus Brockhaus, Jun 12 2006
a(26) to a(32) from Rémy Sigrist, Aug 13 2022

A117831 Let S_n be the infinite sequence formed by starting with n and repeatedly reversing the digits and adding 4 to get the next term. Sequence gives number of steps for S_n to reach a cycle, or -1 if no cycle is ever reached.

Original entry on oeis.org

1, 1, 40, 7, 0, 0, 39, 6, 0, 0, 38, 5, 0, 18, 37, 3, 0, 43, 10, 0, 4, 42, 9, 4, 4, 41, 7, 0, 47, 40, 0, 8, 46, 13, 0, 8, 45, 11, 0, 7, 44, 0, 12, 50, 17, 3, 12, 49, 15, 1, 11, 48, 1, 16, 36, 3, 0, 16, 35, 1, 0, 41, 8, 2, 2, 40, 7, 2, 2, 39, 5, 0, 45, 12, 0, 6, 44, 11, 0, 6, 43, 9, 0, 49, 42, 0, 10
Offset: 1

Views

Author

N. J. A. Sloane, following discussions with Luc Stevens, May 03 2006

Keywords

Comments

It is conjectured that S_n always reaches a cycle.
There are 22 different cycles of length 90 with 4-digit components. I guess that at most half of the numbers between 1000 and 10000 lead to the cycle of length 54 shown in A117830. - Klaus Brockhaus, May 05 2006

Crossrefs

S_1 is given in A117828, S_3 in A117829, S_1015 in A117807.
Records are in A118473, A118474.
Full list of sequences on this topic (1): A117230, A117521, A117800, A117816, A117817, A117827, A117828, A117829, A117830, A117831 (this sequence)
Full list of sequences on this topic (2): A117837, A117841, A118473, A118474, A118510, A118511, A118512, A118513, A118514, A118515, A118516
Full list of sequences on this topic (3): A118517-A118533, A118535

Programs

  • Maple
    V:= Vector(10^5,-1):
    f:= proc(n)
      local L, H, S, i, j,found,x,y;
      global V;
      S:= {n}: H:= n; x:= n;
      for i from 1 to 10^5 do
        if V[x] > -1 then
           for j from 1 to i-1 do V[H[j]]:= i-j+V[x] od;
           return V[n];
        fi;
        L:= convert(x,base,10);
        x:= add(L[-j]*10^(j-1),j=1..nops(L)) + 4;
        if member(x, S) then
          found:= false; y:= 0;
          V[x]:= 0;
          for j from i by -1 to 1 do
            if H[j] = x then found:= true
            elif not found then V[H[j]]:= 0
            else y:= y+1; V[H[j]]:= y;
            fi
          od;
          return V[n]
        fi;
        H:= H, x;
        S:= S union {x};
      od;
    end proc:
    map(f, [$1..200]); # Robert Israel, May 07 2020

Extensions

Corrected and extended by Klaus Brockhaus, May 05 2006
Confirmed by N. J. A. Sloane, May 05 2006

A117521 Start with 1 and repeatedly reverse the digits and add 2 to get the next term.

Original entry on oeis.org

1, 3, 5, 7, 9, 11, 13, 33, 35, 55, 57, 77, 79, 99, 101, 103, 303, 305, 505, 507, 707, 709, 909, 911, 121, 123, 323, 325, 525, 527, 727, 729, 929, 931, 141, 143, 343, 345, 545, 547, 747, 749, 949, 951, 161, 163, 363, 365, 565, 567, 767, 769, 969, 971, 181, 183, 383, 385, 585, 587, 787, 789, 989, 991, 201, 104, 403, 306, 605, 508, 807, 710, 19, 93, 41, 16, 63, 38, 85, 60, 8, 10, 3, 5, 7, 9, 11, 13, 33, 35, 55, 57, 77, 79, 99, 101, 103, 303, 305, 505, 507, 707
Offset: 1

Views

Author

N. J. A. Sloane, following discussions with Luc Stevens, May 04 2006

Keywords

Crossrefs

Formula

After 1 step enters a cycle of length 81.

A120214 Start with 1013 and repeatedly reverse the digits and add 2 to get the next term.

Original entry on oeis.org

1013, 3103, 3015, 5105, 5017, 7107, 7019, 9109, 9021, 1211, 1123, 3213, 3125, 5215, 5127, 7217, 7129, 9219, 9131, 1321, 1233, 3323, 3235, 5325, 5237, 7327, 7239, 9329, 9241, 1431, 1343, 3433, 3345, 5435, 5347, 7437, 7349, 9439, 9351, 1541, 1453, 3543
Offset: 1

Views

Author

Klaus Brockhaus, Jun 11 2006

Keywords

Comments

Let T(S,Q) be the sequence obtained by starting with S and repeatedly reversing the digits and adding Q to get the next term. This is T(1013,2). 1013 is the first S for which T(S,2) reaches a cycle of length 90. The cycle is simply the first 90 terms, which then repeat. A full period is given in the table.

Crossrefs

Programs

  • Mathematica
    NestList[IntegerReverse[#]+2&,1013,50] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 16 2016 *)

A120216 Start with 100013 and repeatedly reverse the digits and add 2 to get the next term.

Original entry on oeis.org

100013, 310003, 300015, 510005, 500017, 710007, 700019, 910009, 900021, 120011, 110023, 320013, 310025, 520015, 510027, 720017, 710029, 920019, 910031, 130021, 120033, 330023, 320035, 530025, 520037, 730027, 720039, 930029, 920041, 140031
Offset: 1

Views

Author

Klaus Brockhaus, Jun 11 2006

Keywords

Comments

Let T(S,Q) be the sequence obtained by starting with S and repeatedly reversing the digits and adding Q to get the next term. This is T(100013,2). 100013 is the first S for which T(S,2) reaches a cycle of length 1890. The cycle is simply the first 1890 terms, which then repeat. A full period is given in the table.

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits[Reverse[IntegerDigits[#]]]+2&,100013,30] (* Harvey P. Dale, Oct 03 2014 *)

A120217 Start with 100057 and repeatedly reverse the digits and add 2 to get the next term.

Original entry on oeis.org

100057, 750003, 300059, 950005, 500061, 160007, 700063, 360009, 900065, 560011, 110067, 760013, 310069, 960015, 510071, 170017, 710073, 370019, 910075, 570021, 120077, 770023, 320079, 970025, 520081, 180027, 720083, 380029, 920085, 580031
Offset: 1

Views

Author

Klaus Brockhaus, Jun 11 2006

Keywords

Comments

Let T(S,Q) be the sequence obtained by starting with S and repeatedly reversing the digits and adding Q to get the next term. This is T(100057,2). 100057 is the first S for which T(S,2) reaches a cycle of length 945. The cycle is simply the first 945 terms, which then repeat. A full period is given in the table.

Crossrefs

A120218 Start with 100103 and repeatedly reverse the digits and add 2 to get the next term.

Original entry on oeis.org

100103, 301003, 300105, 501005, 500107, 701007, 700109, 901009, 900111, 111011, 110113, 311013, 310115, 511015, 510117, 711017, 710119, 911019, 910121, 121021, 120123, 321023, 320125, 521025, 520127, 721027, 720129, 921029, 920131, 131031
Offset: 1

Views

Author

Klaus Brockhaus, Jun 11 2006

Keywords

Comments

Let T(S,Q) be the sequence obtained by starting with S and repeatedly reversing the digits and adding Q to get the next term. This is T(100103,2). 100103 is the first S for which T(S,2) reaches a cycle of length 900. The cycle is simply the first 900 terms, which then repeat. A full period is given in the table.

Crossrefs

Programs

  • Mathematica
    NestList[FromDigits[Reverse[IntegerDigits[#]]]+2&,100103,30] (* Harvey P. Dale, Aug 14 2012 *)

A120215 Start with 1057 and repeatedly reverse the digits and add 2 to get the next term.

Original entry on oeis.org

1057, 7503, 3059, 9505, 5061, 1607, 7063, 3609, 9065, 5611, 1167, 7613, 3169, 9615, 5171, 1717, 7173, 3719, 9175, 5721, 1277, 7723, 3279, 9725, 5281, 1827, 7283, 3829, 9285, 5831, 1387, 7833, 3389, 9835, 5391, 1937, 7393, 3939, 9395, 5941, 1497, 7943, 3499, 9945, 5501
Offset: 1

Views

Author

Klaus Brockhaus, Jun 11 2006

Keywords

Comments

Let T(S,Q) be the sequence obtained by starting with S and repeatedly reversing the digits and adding Q to get the next term. This is T(1057,2). 1057 is the first S for which T(S,2) reaches a cycle of length 45. The cycle is simply the first 45 terms, which then repeat. A full period is shown.

Crossrefs

Programs

  • Mathematica
    NestList[IntegerReverse[#]+2&,1057,50] (* Harvey P. Dale, Jan 25 2021 *)

Formula

a(n) = a(n-45). - Boštjan Gec, Sep 21 2023
Showing 1-9 of 9 results.