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.

Previous Showing 11-17 of 17 results.

A116056 n and pi(n) are both made of nontrivial runs of identical digits, where pi(n)=A000720(n).

Original entry on oeis.org

33, 8833, 66644, 66777, 117766, 118811, 990000, 1144000, 9997777, 115522333, 116660044, 116661111, 1100088555, 1100088855, 1100111100, 1100111111, 1100111333, 1100112200, 1100112211, 1100112222, 2277334444, 2277334455, 2277334466, 2277334477, 2277335500, 2288811222
Offset: 1

Views

Author

Giovanni Resta, Feb 13 2006

Keywords

Comments

A run of length 1 is trivial.
Up to 10^18 there are only 5 prime terms: 9997777, 1122991155533399, 44770077777722233, 440009996622997711, 442244499338866333. - Giovanni Resta, Sep 13 2019

Examples

			pi(118811) = 11199, pi(9997777) = 664444.

Links

Crossrefs

Cf. A000720, A033023, A103357.

Programs

  • Mathematica
    zyQ[n_] := Min[Length /@ Split[IntegerDigits[n]]] > 1; Select[Range[10^7], zyQ[#] && zyQ[PrimePi[#]] &] (* Giovanni Resta, Sep 13 2019 *)

Extensions

More terms from Giovanni Resta, Sep 13 2019

A116062 Brilliant numbers (A078972) made of nontrivial runs of identical digits.

Original entry on oeis.org

22999, 55577, 1166111, 2211133, 2224499, 3377333, 4466333, 5551177, 5555533, 5566999, 5588899, 6622277, 6644333, 6644777, 6660077, 6667799, 7711177, 7711199, 7744111, 7766333, 7771199, 7777999, 7799777, 8866699, 8888777
Offset: 1

Views

Author

Giovanni Resta, Feb 13 2006

Keywords

Comments

A run of length 1 is trivial.

Examples

			8866699 = 2287*3877.

Crossrefs

Cf. A033023, A078972.

A116063 Semiprimes (A001358) made of nontrivial runs of identical digits.

Original entry on oeis.org

22, 33, 55, 77, 111, 1111, 1133, 1177, 1199, 3377, 4411, 4499, 5533, 5599, 6611, 6677, 7711, 7799, 8899, 9977, 11111, 11199, 11333, 11555, 22233, 22255, 22299, 22333, 22999, 33322, 44222, 44333, 44411, 44477, 44999, 55111, 55222, 55577
Offset: 1

Views

Author

Giovanni Resta, Feb 13 2006

Keywords

Comments

A run of length 1 is trivial.

Examples

			44477 = 79*563

Crossrefs

Cf. A001358, A033023, A116062.

A116055 Triangular numbers whose representation is made of nontrivial runs of identical digits.

Original entry on oeis.org

55, 66, 666, 2211, 222111, 339900, 1188111, 22221111, 88000011, 111221155, 553330011, 2200066611, 2222211111, 2233558866, 55666666611, 77771144466, 222222111111, 880022001111, 888000000111, 1111226666655, 5533355001111
Offset: 1

Views

Author

Giovanni Resta, Feb 13 2006

Keywords

Comments

A run of length 1 is trivial.

Examples

			T(14914) = 111221155.

Crossrefs

Cf. A033023.

A116057 n times pi(n) is made of nontrivial runs of identical digits, where pi(n)=A000720(n).

Original entry on oeis.org

11, 37, 66, 154, 332, 750, 1696, 4000, 13684, 22308, 26640, 26653, 30327, 47109, 57941, 67127, 82168, 111438, 112525, 193501, 222553, 250000, 340019, 362725, 522015, 644487, 739552, 836750, 1204350, 1216138, 1216578, 1713376, 1722205
Offset: 1

Views

Author

Giovanni Resta, Feb 13 2006

Keywords

Comments

A run of length 1 is trivial.

Examples

			1216138*pi(1216138) = 114400885522.

Crossrefs

Cf. A000720, A033023.

A116061 Palindromic primes made of nontrivial runs of identical digits.

Original entry on oeis.org

11, 1177711, 7722277, 7733377, 331111133, 772222277, 779999977, 992222299, 995555599, 11006660011, 11117771111, 11119991111, 11155555111, 11188888111, 11442224411, 11447774411, 11663336611, 11668886611
Offset: 1

Views

Author

Giovanni Resta, Feb 13 2006

Keywords

Comments

A run of length 1 is trivial.

Crossrefs

Cf. A033023, A034873.

A116065 Numbers k, not ending in 0, such that k times its digital reverse gives a number made of nontrivial runs of identical digits.

Original entry on oeis.org

88, 385, 583, 1426, 5236, 5929, 6241, 6325, 9295, 284213, 312482, 1001099, 9901001, 15046244, 44264051, 101127144, 176452305, 220741304, 403147022, 441721101, 469671917, 503254671, 719176964, 1110212002, 1111340003, 1315098605, 2002120111, 2024968033, 2433379564
Offset: 1

Views

Author

Giovanni Resta, Feb 13 2006

Keywords

Comments

A run of length 1 is trivial.

Examples

			15046244 * 44264051 = 666007711774444.
5236 * 6325 = 33117700.

Crossrefs

Cf. A033023, A061205.

Programs

  • Mathematica
    okQ[n_]:=Module[{idn=IntegerDigits[n],revnt},revnt=n FromDigits[Reverse[ idn]]; Last[idn]!=0&&Min[Length/@Split[ IntegerDigits[revnt]]]>1]; Select[Range[10^6],okQ] (* Harvey P. Dale, Jan 04 2012 *)

Extensions

Corrected and extended by Giovanni Resta, Aug 30 2025
Incorrect comment removed by Jason Yuen, Aug 30 2025
Previous Showing 11-17 of 17 results.

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