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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A119121 Triangular numbers composed of digits {1,3,9}.

Original entry on oeis.org

1, 3, 91, 193131, 9939111, 119993391339919111, 199913191913191191, 399139119131339931, 139191313119199339131, 1313933311991311991139331, 3131199393919119319199931, 31313993393319311993391131311, 1191131333139133131313199933931
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A119122. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119122(n)).

Extensions

a(13) from Tyler Busby, Mar 28 2023

A119123 Triangular numbers composed of digits {1,4,5}.

Original entry on oeis.org

1, 15, 45, 55, 5151, 44551, 45451, 1551441, 51141441, 51151555, 114511411, 4141455555, 44144455545, 5541155454555, 54145555454451, 114514415144451, 455441144111551, 1151514555151555, 5144441415145515, 45441555441511411, 444441144541554111, 45545414514441444141
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053897, A119124. See A119033 for a table of cross-references.

Programs

  • Mathematica
    Select[Flatten[Table[FromDigits/@Tuples[{1,4,5},n],{n,17}]],OddQ[Sqrt[8#+1]]&] (* Harvey P. Dale, Feb 19 2023 *)

Formula

a(n) = A000217(A119124(n)). - Michel Marcus, Mar 23 2023

Extensions

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

A119125 Triangular numbers composed of digits {1,4,6}.

Original entry on oeis.org

1, 6, 66, 666, 6441, 41616, 146611, 464166, 1464616, 4114146, 14116641, 664611111, 1164441411, 16646464416, 41641661166, 66114661161, 144161141446, 161646441166, 1464464661166, 4464411144441, 44416146616416, 61116114144646, 466141616644641, 1116644466666141, 1161666441164166
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A027676, A119126. See A119033 for a table of cross-references.

Programs

  • Mathematica
    Table[Select[FromDigits/@Tuples[{1,4,6},n],OddQ[Sqrt[8#+1]]&],{n,16}]//Flatten (* Harvey P. Dale, Jun 20 2023 *)

Formula

a(n) = A000217(A119126(n)). - Michel Marcus, Mar 22 2023

Extensions

a(22)-a(24) from Tyler Busby, Mar 22 2023
a(25) from Harvey P. Dale, Jun 20 2023

A119128 Triangular numbers composed of digits {1,4,8}.

Original entry on oeis.org

1, 114481, 1188111, 11841411, 488184144441, 8888818418481, 114841884884181, 144118118141481, 484118414411448411, 141488881884888144481881, 148418181848481418444484488141, 141848488814448448184488111481811, 8114481418814448448488484488444141
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Comments

a(14) > 10^40. - Tyler Busby, Mar 28 2023

Links

Crossrefs

Cf. A000217, A053901, A119129. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119129(n)). - Tyler Busby, Mar 28 2023

Extensions

a(12)-a(13) from Max Alekseyev, Aug 16 2013

A119130 Triangular numbers composed of digits {1,4,9}.

Original entry on oeis.org

1, 91, 49141, 144991, 94414411, 941194191, 1194944941, 491919414441, 9999119991411411, 4149449911949149941, 11144994144991949991, 191444491991911949911, 144949944191119411441191, 9449441991199141999494149499499111914141
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A006716, A119131. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119131(n)). - Tyler Busby, Mar 31 2023

Extensions

a(14) from Max Alekseyev, Aug 15 2013

A119132 Triangular numbers composed of digits {1,5,6}.

Original entry on oeis.org

1, 6, 15, 55, 66, 561, 666, 5151, 5565, 6555, 55611, 56616, 111156, 511566, 565516, 651511, 1565565, 5556111, 5566116, 5656566, 5666661, 15615666, 16666651, 51151555, 55561611, 61566156, 65111166, 116151661, 555561111, 555661116, 556561566, 556661661
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053903, A119133. See A119033 for a table of cross-references.

Programs

  • Mathematica
    Select[FromDigits/@Flatten[Table[Tuples[{1,5,6},n],{n,9}], 1],OddQ[ Sqrt[ 8#+1]]&] (* Harvey P. Dale, Jul 25 2015 *)

Formula

a(n) = A000217(A119133(n)). - Tyler Busby, Mar 31 2023

Extensions

a(31)-a(32) from Tyler Busby, Mar 23 2023

A119134 Triangular numbers composed of digits {1,5,7}.

Original entry on oeis.org

1, 15, 55, 171, 1711, 5151, 11175, 551775, 1777555, 17555775, 51151555, 115117551, 1115171151, 151577151715, 171115717515, 551171777775, 1175175575155, 1577775175717755, 5511171777517575, 7571117555155155, 517577151571517115, 757171775575551115
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A119135. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119135(n)). - Tyler Busby, Mar 31 2023

Extensions

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

A119136 Triangular numbers composed of digits {1,5,8}.

Original entry on oeis.org

1, 15, 55, 5151, 8515, 581581, 885115, 1188111, 11188815, 51151555, 81581151, 88851115, 851585815, 8888511115, 888885111115, 88888851111115, 8888888511111115, 888888885111111115, 5885188811851888815, 15158585181118581555, 88888888851111111115
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053905, A119137. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119137(n)). - Michel Marcus, Mar 24 2023

Extensions

a(20)-a(21) from Tyler Busby, Mar 23 2023

A119138 Triangular numbers composed of digits {1,5,9}.

Original entry on oeis.org

1, 15, 55, 91, 595, 5151, 5995, 9591, 1511191, 51151555, 195911115, 511151999595, 519191199555, 555595555515, 595151955555, 591915955919511, 15995115959551911, 159955559191119511, 9199995595111955111955555, 1559111919555519991599911911
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A119139. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119139(n)). - Tyler Busby, Mar 28 2023

Extensions

a(20) from Tyler Busby, Mar 28 2023

A119140 Triangular numbers composed of digits {1,6,7}.

Original entry on oeis.org

1, 6, 66, 171, 666, 1176, 1711, 17766, 61776, 67161, 166176, 617716, 7767711, 61677171, 77171676, 161667171, 166777716, 611677776, 66767167176, 77111161116, 171676611666, 617617761166, 1116177116671, 161776717667666676, 1116166667661771771, 6667177116611677771
Offset: 1

Views

Author

Giovanni Resta, May 10 2006

Keywords

Links

Crossrefs

Cf. A000217, A053907, A119141. See A119033 for a table of cross-references.

Formula

a(n) = A000217(A119141(n)). - Michel Marcus, Mar 22 2023

Extensions

a(24)-a(26) from Tyler Busby, Mar 22 2023
Previous Showing 51-60 of 112 results. Next

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