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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A119101 Triangular numbers composed of digits {1,2,5}.

Original entry on oeis.org

1, 15, 21, 55, 1225, 2211, 5151, 15225, 21115, 22155, 151525, 222111, 255255, 11551221, 12552555, 21115251, 22221111, 51151555, 111221155, 251115255, 2222211111, 2552515525, 111251152551, 122515222515, 222222111111, 1125152255151, 2522551111515, 5255121522225
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A031153, A119102. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119102(n)). - Michel Marcus, Mar 22 2023

Extensions

a(26)-a(28) from Tyler Busby, Mar 22 2023

A119103 Triangular numbers composed of digits {1,2,6}.

Original entry on oeis.org

1, 6, 21, 66, 666, 2211, 6216, 212226, 222111, 1222266, 1261666, 16626261, 22121226, 22221111, 121111266, 126222216, 661261161, 2162616261, 2221211226, 2222211111, 21166222626, 66126661611, 166122226621, 216262612611, 222212111226, 222222111111, 22162261612611
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053883, A119104. See A119033 for a table of cross-references.

Programs

  • Mathematica
    Flatten[Table[Select[FromDigits/@Tuples[{1,2,6},n],OddQ[Sqrt[8#+1]]&],{n,12}]] (* Harvey P. Dale, Mar 07 2015 *)

Formula

a(n) = A000217(A119104(n)). - Michel Marcus, Mar 16 2023

Extensions

a(24)-a(27) from Tyler Busby, Mar 14 2023

A119105 Triangular numbers composed of digits {1,2,7}.

Original entry on oeis.org

1, 21, 171, 1711, 2211, 72771, 121771, 222111, 712221, 22221111, 72222171, 2222211111, 12177127711, 72177771711, 171277217121, 222222111111, 22222221111111, 121727717277211, 2222222211111111, 22117121117271271, 222222222111111111, 12172172111271712221
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053885, A119106. See A119033 for a table of cross-references.

Programs

  • Mathematica
    Flatten[Table[Select[FromDigits/@Tuples[{1,2,7},n],OddQ[Sqrt[8#+1]]&],{n,17}]] (* Harvey P. Dale, Sep 02 2015 *)

Formula

a(n) = A000217(A119106(n)). - Tyler Busby, Mar 31 2023

Extensions

a(21)-a(22) from Tyler Busby, Mar 23 2023

A119107 Triangular numbers composed of digits {1,2,8}.

Original entry on oeis.org

1, 21, 28, 1128, 2211, 8128, 118828, 222111, 821121, 828828, 881128, 1188111, 1828828, 22221111, 28218828, 88811128, 1821212128, 2222211111, 8888111128, 222222111111, 888881111128, 22222221111111, 88888811111128, 1122211112118111, 2222222211111111
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053887, A119108. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119108(n)). - Michel Marcus, Mar 23 2023

Extensions

a(24)-a(25) from Tyler Busby, Mar 23 2023

A119109 Triangular numbers composed of digits {1,2,9}.

Original entry on oeis.org

1, 21, 91, 2211, 222111, 22221111, 229119121, 291212911, 2222211111, 222222111111, 299992122991, 1122921211191, 22222221111111, 2222222211111111, 21212929921912191, 222222222111111111, 22222222221111111111, 2222222222211111111111, 191929912211129991991191
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053889, A119110. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119110(n)). - Tyler Busby, Mar 31 2023

Extensions

a(17)-a(19) from Tyler Busby, Mar 22 2023

A119111 Triangular numbers composed of digits {1,3,4}.

Original entry on oeis.org

1, 3, 1431, 33411, 331441131, 1444343131, 13113334431, 31444341333441, 111413314441131, 444334341314331, 11114441143333344141, 331341331134344133331, 4443314433131433343331311434133434431331
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Comments

a(14) > 10^41. - Tyler Busby, Mar 27 2023

Links

Crossrefs

Cf. A000217, A053891, A119112. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119112(n)). - Tyler Busby, Mar 27 2023

Extensions

a(13) from Tyler Busby, Mar 27 2023

A119113 Triangular numbers composed of digits {1,3,5}.

Original entry on oeis.org

1, 3, 15, 55, 153, 351, 5151, 33153, 35511, 3531153, 3555111, 35133153, 51151555, 51313515, 355311153, 355551111, 1553111511, 5135151153, 5351313331, 15533353153, 35553111153, 35555511111, 153335313531, 155315331153, 315331155153, 355333351555, 1353153151155
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A119114. See A119033 for a table of cross-references.

Programs

  • Mathematica
    Select[Accumulate[Range[1000000]],Union[Drop[DigitCount[#], {1,5,2}]]=={0}&]  (* Harvey P. Dale, Apr 16 2011 *)
Table[Select[FromDigits/@Tuples[{1,3,5},n],OddQ[Sqrt[8#+1]]&],{n,12}]//Flatten (* Harvey P. Dale, Aug 02 2022 *)

Formula

a(n) = A000217(A119114(n)). - Michel Marcus, Mar 22 2023

Extensions

a(25)-a(27) from Tyler Busby, Mar 22 2023

A119115 Triangular numbers composed of digits {1,3,6}.

Original entry on oeis.org

1, 3, 6, 36, 66, 136, 666, 13366, 333336, 6631661361, 113113613161, 663363661366, 16116313316131, 633161111666331, 633613661136316, 1331116613613361, 33311633636366361, 663661636336331361, 61163111131316636331, 6313111611636313666666, 1616111661666616161331131
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053893, A119116. See A119033 for a table of cross-references.

Programs

  • Mathematica
    Table[Select[FromDigits/@Tuples[{1,3,6},n],OddQ[Sqrt[8#+1]]&],{n,18}]//Flatten (* Harvey P. Dale, Sep 18 2017 *)

Formula

a(n) = A000217(A119116(n)). - Michel Marcus, Mar 22 2023

Extensions

a(19)-a(21) from Tyler Busby, Mar 22 2023

A119117 Triangular numbers composed of digits {1,3,7}.

Original entry on oeis.org

1, 3, 171, 1711, 1717731, 17131731, 1313137337331, 117717311713137711, 773113771333731171, 3773733771711731311, 177177371373713177137131, 311733717173773173111771, 3311337711173711371777131, 1173713773733717717113371171
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A119118. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119118(n)).

Extensions

a(14) from Tyler Busby, Mar 28 2023

A119119 Triangular numbers composed of digits {1,3,8}.

Original entry on oeis.org

1, 3, 88831, 1188111, 38311881, 11313313831, 83388881331381, 881388838113181838838811, 8138133831331381318318881, 183113183318838311383311313311, 133831381813113188111133181833111, 31188113313888818318833183383131131
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Comments

No other terms below 10^41. - Tyler Busby, Mar 28 2023

Links

Crossrefs

Cf. A000217, A053895, A119120. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119120(n)). - Tyler Busby, Mar 28 2023

Extensions

Two more terms from Max Alekseyev, May 12 2009
Previous Showing 41-50 of 112 results. Next

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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