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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A063057 'Reverse and Add!' trajectory of 7059.

Original entry on oeis.org

7059, 16566, 83127, 155265, 717816, 1336533, 4692864, 9375828, 17661567, 94178238, 177465387, 961030158, 1812060327, 9042662508, 17095324917, 89037683988, 177976357086, 858730036857, 1617360074715, 6792060711876
Offset: 0

Views

Author

Klaus Brockhaus, Jul 07 2001

Keywords

Examples

			a(1) = 7059 + 9507 = 16566.
		

Crossrefs

Programs

  • ARIBAS
    m := 7059; stop := 25; c := 0; rev := int_reverse(m); while m <> rev and c < stop do inc(c); write(m," "); m := m + rev; rev := int_reverse(m); end;
    
  • Haskell
    a063057 n = a063057_list !! n
    a063057_list = iterate a056964 7059 -- Reinhard Zumkeller, Sep 22 2011
  • Mathematica
    NestList[# + FromDigits[Reverse[IntegerDigits[#]]]&, 7059, 40] (* Vincenzo Librandi, May 03 2014 *)

A063054 'Reverse and Add!' trajectory of 1997.

Original entry on oeis.org

1997, 9988, 18887, 97768, 184547, 930028, 1750067, 9350638, 17711177, 94822948, 179745797, 977293768, 1844686547, 9301551028, 17503102067, 93523232638, 177146465177, 948711106948, 1798312224797, 9772534363768, 18446168716547
Offset: 0

Views

Author

Klaus Brockhaus, Jul 07 2001

Keywords

Examples

			a(1) = 1997 + 7991 = 9988.
		

Crossrefs

Programs

  • ARIBAS
    m := 1997; stop := 25; c := 0; rev := int_reverse(m); while m <> rev and c < stop do inc(c); write(m," "); m := m + rev; rev := int_reverse(m); end;
    
  • Haskell
    a063054 n = a063054_list !! n
    a063054_list = iterate a056964 1997 -- Reinhard Zumkeller, Sep 22 2011
  • Mathematica
    NestList[ #+FromDigits[ Reverse[ IntegerDigits[ # ] ] ]&, 1997, 25 ]
    NestList[#+IntegerReverse[#]&,1997,25] (* Harvey P. Dale, Jul 15 2025 *)

A063060 'Reverse and Add!' trajectory of 10553.

Original entry on oeis.org

10553, 46054, 91118, 172237, 904508, 1709917, 8908988, 17807086, 85877957, 161855815, 680413976, 1359728062, 3968007593, 7925016286, 14751121583, 53263237324, 95636473559, 191173937218, 1003913308409, 10051946501410
Offset: 0

Views

Author

Klaus Brockhaus, Jul 07 2001

Keywords

Examples

			a(1) = 10553 + 35501 = 46054.
		

Crossrefs

Programs

  • ARIBAS
    m := 10553; stop := 25; c := 0; rev := int_reverse(m); while m <> rev and c < stop do inc(c); write(m," "); m := m + rev; rev := int_reverse(m); end;
    
  • Haskell
    a063060 n = a063060_list !! n
    a063060_list = iterate a056964 10553 -- Reinhard Zumkeller, Sep 22 2011
  • Mathematica
    NestList[# + FromDigits[Reverse[IntegerDigits[#]]]&, 10553, 40] (* Vincenzo Librandi, May 03 2014 *)

Extensions

Updated b-file from Michael Lee, Apr 01 2012

A063063 'Reverse and Add!' trajectory of 10563.

Original entry on oeis.org

10563, 47064, 93138, 176277, 948948, 1798797, 9777768, 18455547, 93011028, 175022067, 935242638, 1771485177, 9487326948, 17983564797, 97730103768, 184460207547, 930162272028, 1750434533067, 9353788873638, 17717577747177
Offset: 0

Views

Author

Klaus Brockhaus, Jul 07 2001

Keywords

Examples

			a(1) = 10563 + 36501 = 47064.
		

Crossrefs

Programs

  • ARIBAS
    m := 10563; stop := 25; c := 0; rev := int_reverse(m); while m <> rev and c < stop do inc(c); write(m," "); m := m + rev; rev := int_reverse(m); end;
    
  • Haskell
    a063063 n = a063063_list !! n
    a063063_list = iterate a056964 10563 -- Reinhard Zumkeller, Sep 22 2011
  • Mathematica
    NestList[# + FromDigits[Reverse[IntegerDigits[#]]]&, 10563, 30] (* Vincenzo Librandi, May 03 2014 *)

A066054 'Reverse and Add!' trajectory of 10583.

Original entry on oeis.org

10583, 49084, 97178, 184357, 937838, 1776577, 9533348, 17966707, 88733678, 176367466, 841131137, 1572262285, 7394885036, 13700769973, 51697470704, 92404950319, 183710890748, 1030808908129, 10248906988430, 13737867972631
Offset: 0

Views

Author

Klaus Brockhaus, Nov 30 2001

Keywords

Examples

			a(1) = 10583 + 38501 = 49084.
		

Crossrefs

Programs

  • ARIBAS
    : m := 10583; stop := 20; c := 0; rev := int_reverse(m); while m <> rev and c < stop do inc(c); write(m," "); m := m + rev; rev := int_reverse(m); end;
    
  • Haskell
    a066054 n = a066054_list !! n
    a066054_list = iterate a056964 10583 -- Reinhard Zumkeller, Sep 22 2011
  • Mathematica
    NestList[# + FromDigits[Reverse[IntegerDigits[#]]]&,  10583, 40] (* Vincenzo Librandi, May 03 2014 *)
  • PARI
    Rev(x)= { local(d, r=0); while (x>0, d=x%10; x\=10; r=r*10 + d); return(r) } { a=10583; for (n = 0, 150, if (n, a+=Rev(a)); write("b066054.txt", n, " ", a) ) } \\ Harry J. Smith, Nov 08 2009
    

A060382 In base n, a(n) is the smallest number m that leads to a palindrome-free sequence, using the following process: start with m; reverse the digits and add it to m, repeat. Stop if you reach a palindrome.

Original entry on oeis.org

22, 103, 290, 708, 1079, 2656, 1021, 593, 196, 1011, 237, 2701, 361, 447, 413, 3297, 519, 341, 379, 711, 461, 505, 551, 1022, 649, 701, 755, 811, 869, 929, 991, 1055, 1799, 1922, 1259, 1331, 1405, 1481, 1559, 1639, 1595, 1762, 1891, 1934, 2069, 2161
Offset: 2

Views

Author

Michel ten Voorde, Apr 03 2001

Keywords

Comments

Only a(2) is proved, all the others are conjectured. - Eric Chen, Apr 20 2015 [corrected by A.H.M. Smeets, May 27 2019]
Brown's link reports a(3) as 103 instead of 100. What is the correct value? Dmitry Kamenetsky, Mar 06 2017 [a(3) = 103 is correct as from A077404, A.H.M. Smeets, May 27 2019]
From A.H.M. Smeets, May 27 2019: (Start)
It seems that a(n) < n^2 (i.e., a(n) in base n has two digits) and the least significant digit of a(n) in base n equals n-1, for n > 73.
For n <= 73 and the least significant digit of a(n) in base n is unequal to n-1, then the most significant digit of a(n) in base n equals 1.
From this it seems that, the least significant digit of a(n) in base n equals n-1 or the most significant digit of a(n) in base n equals 1, holds for all n > 1.
For n > 305 it seems that a(n) < n^2 - n - 1.
It seems that a(n) >= n*floor(3*n/4)-1; i.e. for any a(n) which is represented by a two-digit number in base n, the most significant digit is at least floor(3*n/4)-1. (End)
From A.H.M. Smeets, May 30 2019: (Start)
a(n) is a 5-digit number in base n representation for n in {2,3,4,5,7}.
a(n) is a 4-digit number in base n representation for n in {6,8,13}.
a(n) is a 3-digit number in base n representation for n in {9,10,11,12,14,15,16,17,18,21,25,34,35,52,71,72,73}.
For all other bases n, a(n) is a 2-digit number in base-n representation.
If a(n) = n*floor(3*n/4)-1, then n == 0 (mod 4) or n == 3 (mod 4). (End)

Examples

			a(2) = 22 since A062129(k) > -1 (equivalently, A062131(k) > -1) for k < 22.
		

Crossrefs

For the first palindrome in non-palindrome-free sequences, cf. A062129/A062131 (base 2), A033865 (base 10), A253241 (base 12).

Programs

  • Python
    def rev(n,base):
        m = 0
        while n > 0:
            n, m = n//base, m*base+n%base
        return m
    n, a, steps = 2, 3, 0
    while n <= 20000:
        aa = a
        ra = rev(a,n)
        while aa != ra and steps < 1000:
            aa = aa+ra
            ra, steps = rev(aa,n), steps+1
        if aa == ra:
            a, aa, steps = a+1, a+1, 0
        if steps == 1000:
            print(n,a)
            n, a, steps = n+1, n+2, 0 # A.H.M. Smeets, May 27 2019

Extensions

More terms from Karl Hovekamp, Jan 03 2007

A063052 Integers n > 879 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 879.

Original entry on oeis.org

978, 1497, 1587, 1677, 1767, 1857, 1947, 2496, 2586, 2676, 2766, 2856, 2946, 3495, 3585, 3675, 3765, 3855, 3945, 4494, 4584, 4674, 4764, 4854, 4944, 5493, 5583, 5673, 5763, 5853, 5943, 6492, 6582, 6672, 6762, 6852, 6942, 7491, 7581, 7671, 7761, 7851
Offset: 1

Views

Author

Klaus Brockhaus, Jul 07 2001

Keywords

Comments

Subsequence of A023108.

Examples

			The trajectory of 1497 reaches 9438 in one step and 9438 is a term in the trajectory of 879, so 1497 belongs to the present sequence. The corresponding term in A063053, giving the number of steps, accordingly is 1.
		

Crossrefs

Extensions

Offset corrected by Sean A. Irvine, Apr 17 2023

A063055 Integers n > 1997 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 1997.

Original entry on oeis.org

2996, 3995, 5993, 6992, 7991, 8089, 8179, 8269, 8359, 8449, 8539, 8629, 8719, 8809, 8899, 8989, 8990, 9088, 9178, 9268, 9358, 9448, 9538, 9628, 9718, 9808, 9898, 9988, 13397, 14387, 15377, 16367, 17357, 17897, 18347, 18887, 19337, 19877, 23396
Offset: 0

Views

Author

Klaus Brockhaus, Jul 07 2001

Keywords

Comments

Subsequence of A023108.

Examples

			The trajectory of 3995 reaches 9988 in one step and 9988 is a term in the trajectory of 1997, so 3995 belongs to the present sequence. The corresponding term in A063056, giving the number of steps, accordingly is 1.
		

Crossrefs

A063058 Integers n > 7059 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 7059.

Original entry on oeis.org

7149, 7239, 7329, 7419, 7509, 7599, 7689, 7779, 7869, 7959, 8058, 8148, 8238, 8328, 8418, 8508, 8598, 8688, 8868, 8958, 9057, 9147, 9237, 9327, 9417, 9507, 9597, 9687, 9777, 9867, 9957, 13596, 14586, 15576, 16566, 17292, 17556, 18096, 18282, 18546
Offset: 0

Views

Author

Klaus Brockhaus, Jul 07 2001

Keywords

Comments

Subsequence of A023108.

Examples

			The trajectory of 7239 reaches 16566 in one step and 16566 is a term in the trajectory of 7059, so 7239 belongs to the present sequence. The corresponding term in A063059, giving the number of steps, accordingly is 1.
		

Crossrefs

A063061 Integers n > 10553 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 10553.

Original entry on oeis.org

11543, 12097, 12533, 13087, 13523, 14077, 14513, 15067, 15503, 16057, 16597, 17047, 17587, 18037, 18577, 19027, 19567, 20552, 21542, 22096, 22532, 23086, 23522, 24076, 24512, 25066, 25502, 26056, 26596, 27046, 27586, 28036, 28576
Offset: 0

Views

Author

Klaus Brockhaus, Jul 07 2001

Keywords

Comments

Subsequence of A023108.

Examples

			The trajectory of 12097 reaches 91118 in one step and 91118 is a term in the trajectory of 10553, so 12097 belongs to the present sequence. The corresponding term in A063062, giving the number of steps, accordingly is 1.
		

Crossrefs

Previous Showing 21-30 of 42 results. Next