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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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
    

A244567 Triangle T(n,k) in which the n-th row lists in increasing order all values s such that n is in the trajectory of the 'Reverse and Add!' sequence starting with s; triangle T(n,k), n>=0, 1<=k<=A244569(n), read by rows.

Original entry on oeis.org

0, 1, 1, 2, 3, 1, 2, 4, 5, 3, 6, 7, 1, 2, 4, 8, 9, 5, 10, 5, 10, 11, 3, 6, 12, 13, 7, 14, 15, 1, 2, 4, 8, 16, 17, 9, 18, 19, 20, 21, 5, 10, 11, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 3, 6, 12, 21, 30, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43
Offset: 0

Views

Author

Alois P. Heinz, Jun 30 2014

Keywords

Examples

			Triangle T(n,k) begins:
   0;
   1;
   1,  2;
   3;
   1,  2,  4;
   5;
   3,  6;
   7;
   1,  2,  4,  8;
   9;
   5, 10;
   5, 10, 11;
   3,  6, 12;
  13;
   7, 14;
  15;
   1,  2,  4,  8,  16;
  17;
		

Crossrefs

Column k=0 gives A244568.
Last elements of rows give A001477.

A244568 Smallest value s such that n is in the trajectory of the 'Reverse and Add!' sequence starting with s.

Original entry on oeis.org

0, 1, 1, 3, 1, 5, 3, 7, 1, 9, 5, 5, 3, 13, 7, 15, 1, 17, 9, 19, 20, 21, 5, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 3, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 5, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 7, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 3, 67, 68, 69
Offset: 0

Views

Author

Alois P. Heinz, Jun 30 2014

Keywords

Crossrefs

A244569 Number of values s such that n is in the trajectory of the 'Reverse and Add!' sequence starting with s.

Original entry on oeis.org

1, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 3, 3, 1, 2, 1, 5, 1, 2, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 6, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 12, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 17
Offset: 0

Views

Author

Alois P. Heinz, Jun 30 2014

Keywords

Crossrefs

A030547 Number of terms (including the initial term) needed to reach a palindrome when the Reverse Then Add! map (x -> x + (x-with-digits-reversed)) is repeatedly applied to n, or -1 if a palindrome is never reached.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 1, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 1, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 1, 2, 3, 2, 3, 3, 2, 2, 2, 2, 2, 1, 2, 3, 3, 4, 2, 2, 2, 2, 3, 2, 1, 3, 4, 5, 2, 2, 2, 3, 2, 3, 3, 1, 5, 7, 2, 2, 3, 2, 3, 3, 4, 5, 1, 25, 2, 3, 2, 3, 3, 4, 5, 7, 25
Offset: 1

Views

Author

Keywords

Comments

It is conjectured that a(196) is the smallest term equal to -1. See A023108.

References

  • Daniel Lignon, Dictionnaire de (presque) tous les nombres entiers, Ellipses, Paris, 2012, 702 pages. See Entry 196.

Crossrefs

Cf. A006960, A023108, A063018, etc.
Equals A033665(n) + 1.

Programs

  • Mathematica
    Table[Length@
      NestWhileList[# + IntegerReverse[#] &, n, ! PalindromeQ[#]  &], {n, 98}] (* Robert Price, Oct 18 2019 *)

Extensions

Edited by N. J. A. Sloane, May 09 2015

A244058 n-th term of the 'Reverse and Add!' sequence starting with n.

Original entry on oeis.org

1, 4, 12, 77, 44, 363, 484, 4444, 79497, 14003, 88088, 175857, 1596595, 1716517, 17794887, 13528163, 176599676, 839546037, 1317544822, 853595347, 8836886388, 13236127322, 13297007933, 668823329856, 175304440267, 909153350908, 9317488848228, 8813200023188
Offset: 1

Views

Author

Alois P. Heinz, Jun 18 2014

Keywords

Comments

a(n) is a palindrome for n in {1, 2, 4, 5, 6, 7, 8, 9, 11, 21, 28, 30}.

Crossrefs

Main diagonal of A243238.

Programs

  • Maple
    b:= proc(n, j) option remember; `if`(j=1, n, (h-> h+ (s->
          parse(cat(s[-i]$i=1..length(s))))(""||h))(b(n, j-1)))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=1..40);
  • Mathematica
    Table[Nest[#+IntegerReverse[#]&,n,n-1],{n,30}] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 07 2021 *)

A273228 G.f. is the fourth power of the g.f. of A006950.

Original entry on oeis.org

1, 4, 10, 24, 55, 116, 230, 440, 819, 1480, 2602, 4480, 7580, 12604, 20620, 33272, 53029, 83520, 130088, 200600, 306488, 464168, 697150, 1039032, 1537435, 2259300, 3298428, 4785880, 6903657, 9903040, 14129846, 20058488, 28336790, 39845456, 55778050, 77747328, 107924347, 149221160
Offset: 0

Views

Author

M.S. Mahadeva Naika, May 18 2016

Keywords

Comments

Ramanujan theta functions: f(q) (see A121373), phi(q) (A000122), psi(q) (A010054), chi(q) (A000700).

Crossrefs

Programs

  • Maple
    Digits:=200:with(PolynomialTools): with(qseries): with(ListTools):
    GenFun:=series(etaq(q,2,1000)^4/etaq(q,1,1000)^4/etaq(q,4,1000)^4,q,50):
    CoefficientList(sort(convert(GenFun,polynom),q,ascending),q);
  • Mathematica
    nmax = 30; CoefficientList[Series[Product[(1 + x^k)^4 / (1 - x^(4*k))^4, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Mar 25 2017 *)
    CoefficientList[Series[1/(QPochhammer[q, -q]*QPochhammer[q^2, q^2])^4, {q, 0, 50}], q] (* G. C. Greubel, Apr 17 2018 *)

Formula

G.f.: Product_{k>=1} (1 + x^k)^4 / (1 - x^(4*k))^4, corrected by Vaclav Kotesovec, Mar 25 2017
Expansion of 1 / psi(-x)^4 in powers of x where psi() is a Ramanujan theta function.
a(n) ~ exp(sqrt(2*n)*Pi) / (2^(9/4)*n^(7/4)). - Vaclav Kotesovec, Mar 25 2017

Extensions

Edited by N. J. A. Sloane, May 26 2016
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