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.

A068665 a(1) = 3; a(n) = smallest palindromic multiple of a(n-1).

Original entry on oeis.org

3, 6, 66, 858, 6006, 66066, 858858, 222444222, 444888444, 21354645312, 21375999957312, 211643775577346112, 211432343445544343234112, 21354666687999978666645312, 211432554877887788778455234112, 211221333755564778877465557333122112
Offset: 1

Views

Author

Amarnath Murthy, Mar 01 2002

Keywords

Links

Crossrefs

Cf. A068664, A068666, A068667, A068668, A070069, A068971, A068972, A068973, A068974, A083149.

Programs

  • Mathematica
    a[1] = 3; a[n_] := a[n] = Block[{k = 2}, While[k*a[n - 1] != ToExpression[ StringReverse[ ToString[k*a[n - 1]]]], k++ ]; k*a[n - 1]]; Table[a[n], {n, 1, 16}]
nxt[n_]:=Module[{k=2},While[k*n!=IntegerReverse[k*n],k++];k*n]; NestList[ nxt,3,15] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 14 2016 *)

Extensions

More terms from David W. Wilson; edited by Patrick De Geest, Mar 30 2002
a(16) from Giovanni Resta, Sep 22 2019

A068664 a(1) = 1, a(n) = smallest palindromic multiple of a(n-1).

Original entry on oeis.org

1, 2, 4, 8, 88, 616, 6776, 88088, 616616, 232464232, 21154245112, 232696696232, 21175399357112, 21154245133154245112, 232696696464696696232, 21175399378287399357112, 63386501441764911946714410568336
Offset: 1

Views

Author

Amarnath Murthy, Mar 01 2002

Keywords

Crossrefs

A068667 (from a(3) on) and this sequence (from a(6) on) coincide.
Cf. A068665, A068666, A068667, A068668, A070069, A068971, A068972, A068973, A068974.

Programs

  • Mathematica
    a=1; Print[a]; For[n = 2, n <= 15, n++, {an = a; k = 2; str = ToString[k*an]; rstr = StringReverse[str]; While[str != rstr, {k = k + 1; str = ToString[k*an]; rstr = StringReverse[str]; If[k*an > 10^20, {Print["Too big"]; Abort[]}]}]; a := k*an; Print[k, " ", a];}]
spm[n_]:=Module[{k=2},While[!PalindromeQ[k*n],k++];k*n]; NestList[spm,1,15] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 02 2019 *)

Extensions

Extended and edited by John W. Layman, Mar 18 2002
Last two terms from David W. Wilson and Patrick De Geest, Mar 30 2002

A068666 a(1) = 5; a(n) = smallest palindromic multiple of a(n-1).

Original entry on oeis.org

5, 55, 5005, 55055, 50155105, 5065665605, 50155155155105, 5464353998993534645, 541025148469303964841520145, 513016415223221833242338122322514610315
Offset: 1

Views

Author

Amarnath Murthy, Mar 01 2002

Keywords

Crossrefs

Cf. A068664, A068665, A068667, A068668, A070069, A068971, A068972, A068973, A068974.

Programs

  • Mathematica
    a[1] = 5; a[n_] := a[n] = Block[{k = 2}, While[k*a[n - 1] != ToExpression[ StringReverse[ ToString[k*a[n - 1]]]], k++ ]; k*a[n - 1]]; Table[a[n], {n, 1, 9}]
spm[n_]:=Module[{k=2},While[!PalindromeQ[k*n],k++];k*n]; NestList[spm,5,10] (* Harvey P. Dale, Nov 10 2022 *)

Extensions

Corrected and extended by David W. Wilson and Patrick De Geest, Mar 30 2002
a(10) from John Gustaf Stebbins, Sep 17 2008

A068667 a(1) = 7; a(n) = smallest palindromic multiple of a(n-1).

Original entry on oeis.org

7, 77, 616, 6776, 88088, 616616, 232464232, 21154245112, 232696696232, 21175399357112, 21154245133154245112, 232696696464696696232, 21175399378287399357112, 63386501441764911946714410568336
Offset: 1

Views

Author

Amarnath Murthy, Mar 01 2002

Keywords

Crossrefs

Cf. A068664 (from a(6) on) and this sequence (from a(3) on) coincide.
Cf. A068664, A068665, A068666, A068668, A070069, A068971, A068972, A068973, A068974.

Programs

  • Mathematica
    a[1] = 7; a[n_] := a[n] = Block[{k = 2}, While[k*a[n - 1] != ToExpression[ StringReverse[ ToString[k*a[n - 1]]]], k++ ]; k*a[n - 1]]; Table[a[n], {n, 1, 14}]
NestList[Module[{k=2},While[!PalindromeQ[k #],k++];k #]&,7,10] (* The program generates the first 11 terms of the sequence. *) (* Harvey P. Dale, Feb 07 2025 *)

Extensions

Last two terms from David W. Wilson, Sascha Kurz and edited by Patrick De Geest, Mar 30 2002

A068971 Multipliers resulting from A068664.

Original entry on oeis.org

2, 2, 2, 11, 7, 11, 13, 7, 377, 91, 11, 91, 999001, 11, 91, 2993402878
Offset: 1

Views

Author

Patrick De Geest, Mar 30 2002

Keywords

Crossrefs

Cf. A068664, A068665, A068666, A068667, A068972, A068973, A068974.

Formula

a(n) = A068664(n+1)/A068664(n). - Jinyuan Wang, Mar 13 2020

A068973 Multipliers resulting from A068666.

Original entry on oeis.org

11, 91, 11, 911, 101, 9901, 108949, 99009901
Offset: 1

Views

Author

Patrick De Geest, Mar 30 2002

Keywords

Crossrefs

Cf. A068664, A068665, A068666, A068667, A068971, A068972, A068974.

Formula

a(n) = A068666(n+1)/A068666(n). - Jinyuan Wang, Mar 13 2020

A068974 Multipliers resulting from A068667.

Original entry on oeis.org

11, 8, 11, 13, 7, 377, 91, 11, 91, 999001, 11, 91, 2993402878
Offset: 1

Views

Author

Patrick De Geest, Mar 30 2002

Keywords

Crossrefs

Cf. A068664, A068665, A068666, A068667, A068971, A068972, A068973.

Formula

a(n) = A068667(n+1)/A068667(n). - Jinyuan Wang, Mar 13 2020

A068668 a(1) = 9; a(n) = smallest palindromic multiple of a(n-1).

Original entry on oeis.org

9, 99, 1881, 171171, 1882881, 306909603, 11355655311, 1033364633301, 1034397997934301, 10241574577547514201, 10231343244544544234313201, 112544775689989986577445211, 1023144555797698967975554413201, 102221350448336861989168633844053122201, 11233003103852144358833233885344125830130033211
Offset: 1

Views

Author

Amarnath Murthy, Mar 01 2002

Keywords

Crossrefs

Cf. A068664, A068665, A068666, A068667, A070069, A068971, A068972, A068973, A068974.

Programs

  • Mathematica
    a[1] = 9; a[n_] := a[n] = Block[{k = 2}, While[k*a[n - 1] != ToExpression[ StringReverse[ ToString[k*a[n - 1]]]], k++ ]; k*a[n - 1]]; Table[a[n], {n, 1, 13}] (* Robert G. Wilson v, Apr 19 2002 *)

Extensions

More terms from Sascha Kurz, Mar 27 2002
Edited by N. J. A. Sloane, Apr 19 2007
a(14)-a(15) from Giovanni Resta, Sep 25 2019

A070069 a(1) = 11; a(n) = smallest palindromic multiple of a(n-1).

Original entry on oeis.org

11, 22, 44, 88, 616, 6776, 88088, 616616, 232464232, 21154245112, 232696696232, 21175399357112, 21154245133154245112, 232696696464696696232, 21175399378287399357112, 63386501441764911946714410568336
Offset: 1

Views

Author

Robert G. Wilson v, Apr 19 2002

Keywords

Crossrefs

Cf. A068664 (from a(5) on) and this sequence (from a(4) on) coincide.
Cf. A068664, A068665, A068666, A068667, A068668, A068971, A068972, A068973, A068974.

Programs

  • Mathematica
    e[1] = 11; e[n_] := e[n] = Block[{k = 2}, While[k*e[n - 1] != ToExpression[ StringReverse[ ToString[k*e[n - 1]]]], k++ ]; k*e[n - 1]]; Table[e[n], {n, 1, 12}]
Showing 1-9 of 9 results.

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