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 1-10 of 13 results. Next

A138126 Indices among the primes of the primes in A020461.

Original entry on oeis.org

2, 14, 84, 86, 471, 481, 3570, 28674, 28743, 29448, 29457, 37293, 37299, 239128, 239793, 239800, 239852, 239864, 245780, 245859, 246469, 246541, 305733, 311548, 311615, 312235, 2108429, 2114208, 2114772, 2629825
Offset: 1

Views

Author

Omar E. Pol, Mar 25 2008

Keywords

Comments

Indices of A054356 (The Five Hysterical Girls Theorem) are members of this sequence (See A138132).

Examples

			a(5)=471 because A020461(5)=3343 and A000040(471)=3343, the 471st prime number.
		

Crossrefs

A199340 Primes having only {0, 3, 4} as digits.

Original entry on oeis.org

3, 43, 433, 443, 3343, 3433, 4003, 30403, 33343, 33403, 34033, 34303, 34403, 40343, 40433, 43003, 43403, 300043, 300343, 304033, 304303, 304433, 330433, 333433, 334043, 334333, 334403, 343303, 343333, 343433, 400033, 403003, 403043, 403433, 430303, 430333
Offset: 1

Views

Author

M. F. Hasler, Nov 05 2011

Keywords

Comments

All terms end in '3'. This could be used to speed up the given program.
A020461 is a subsequence. - Vincenzo Librandi, Jul 23 2015

Crossrefs

Cf. Primes that contain only the digits (3,4,k): this sequence (k=0), A199341 (k=1), A199342 (k=2), A199345 (k=5), A199346 (k=6), A199347 (k=7), A199348 (k=8), A199349 (k=9).

Programs

  • Magma
    [p: p in PrimesUpTo(5*10^5) | Set(Intseq(p)) subset [3, 4, 0]]; // Vincenzo Librandi, Jul 23 2015
    
  • Mathematica
    Select[Prime[Range[5 10^4]], Complement[IntegerDigits[#], {3, 4, 0}]=={} &] (* Vincenzo Librandi, Jul 23 2015 *)
    Select[FromDigits/@Tuples[{0,3,4},6],PrimeQ] (* Harvey P. Dale, Mar 21 2020 *)
    Select[10#+3&/@FromDigits/@Tuples[{0,3,4},5],PrimeQ] (* Harvey P. Dale, May 02 2022 *)
  • PARI
    a(n, list=0, L=[0, 3, 4], reqpal=0)={my(t); for(d=1, 1e9, u=vector(d, i, 10^(d-i))~; forvec(v=vector(d, i, [1+(i==1&!L[1]), #L]), isprime(t=vector(d, i, L[v[i]])*u)||next; reqpal && !isprime(A004086(t)) && next; list && print1(t", "); n--||return(t)))} \\ Syntax updated for current PARI version. - M. F. Hasler, Jul 25 2015
    
  • PARI
    {forprime(p=3,1e6,p%10==3&&!setminus(Set(digits(p)),[3,4])&&print1(p","))} \\ [0] evaluates to false. - M. F. Hasler, Jul 25 2015

A199349 Primes having only {3, 4, 9} as digits.

Original entry on oeis.org

3, 43, 349, 433, 439, 443, 449, 499, 3343, 3433, 3449, 3499, 3943, 4339, 4349, 4493, 4933, 4943, 4993, 4999, 9343, 9349, 9433, 9439, 9949, 33343, 33349, 33493, 34439, 34499, 34939, 34949, 39343, 39439, 39443, 39499, 43399, 43499, 43933, 43943, 44449, 44939, 49333, 49339, 49393, 49433, 49499, 49939, 49943, 49993
Offset: 1

Views

Author

M. F. Hasler, Nov 05 2011

Keywords

Comments

A020461 and A020466 are subsequences. - Vincenzo Librandi, Jul 30 2015

Crossrefs

Cf. Primes that contain only the digits (3,4,k): A199340 (k=0), A199341 (k=1), A199342 (k=2), A199345 (k=5), A199346 (k=6), A199347 (k=7), A199348 (k=8).

Programs

  • Magma
    [p: p in PrimesUpTo(2*10^5) | Set(Intseq(p)) subset [3, 4, 9]]; // Vincenzo Librandi, Jul 30 2015
  • Mathematica
    Select[Prime[Range[2 10^4]], Complement[IntegerDigits[#], {3, 4, 9}]=={} &] (* Vincenzo Librandi, Jul 30 2015 *)
    Select[Flatten[Table[FromDigits/@Tuples[{3,4,9},n],{n,5}]],PrimeQ] (* Harvey P. Dale, May 02 2023 *)
  • PARI
    a(n, list=0, L=[3,4,9], reqpal=0)={my(t); for(d=1, 1e9, u=vector(d, i, 10^(d-i))~; forvec(v=vector(d, i, [1+(i==1&!L[1]), #L]), isprime(t=vecextract(L,v)*u) || next; reqpal && !isprime(A004086(t)) && next; list && print1(t", "); n--||return(t)))}
    

A020454 Primes that contain digits 1 and 6 only.

Original entry on oeis.org

11, 61, 661, 6661, 11161, 16111, 16661, 66161, 111611, 161611, 611111, 616111, 1111661, 1611161, 1616161, 1616611, 1661111, 1661161, 1666111, 6111661, 6116111, 6116161, 6161161, 6611611, 6661111, 6661661, 11111161, 11166611, 11616611
Offset: 1

Views

Author

Keywords

Programs

  • Magma
    [p: p in PrimesUpTo(11616611) | Set(Intseq(p)) subset [1, 6]]; // Vincenzo Librandi, Jul 27 2012. (see Berselli A020461).
  • Mathematica
    Flatten[Table[Select[FromDigits/@Tuples[{1,6},n],PrimeQ],{n,8}]] (* Vincenzo Librandi, Jul 27 2012 *)
    Select[Flatten[Table[10*FromDigits/@Tuples[{1,6},n]+1,{n,7}]],PrimeQ] (* Slightly faster than the above Mathematica program by forcing the last digit to be one. *) (* Harvey P. Dale, May 31 2018 *)

A199341 Primes having only {1, 3, 4} as digits.

Original entry on oeis.org

3, 11, 13, 31, 41, 43, 113, 131, 311, 313, 331, 431, 433, 443, 1433, 3313, 3331, 3343, 3413, 3433, 4111, 4133, 4441, 11113, 11131, 11311, 11411, 11443, 13313, 13331, 13411, 13441, 14143, 14341, 14411, 14431, 31333, 33113, 33311, 33331, 33343, 33413, 34141, 34313
Offset: 1

Views

Author

M. F. Hasler, Nov 05 2011

Keywords

Comments

A020451, A020452 and A020461 are subsequences. - Vincenzo Librandi, Jul 26 2015

Crossrefs

Cf. similar sequences listed in A199340.

Programs

  • Magma
    [p: p in PrimesUpTo(10^5) | Set(Intseq(p)) subset [3, 4, 1]]; // Vincenzo Librandi, Jul 26 2015
  • Maple
    Dmax:= 5: # to get all terms < 10^Dmax
    Cd:= {1,3,4}:
    C:= Cd:
    for d from 2 to Dmax do
      Cd:= map(t -> (10*t+1,10*t+3,10*t+4),Cd);
      C:= C union Cd;
    od:
    sort(convert(select(isprime,C),list)); # Robert Israel, Jul 26 2015
  • Mathematica
    Select[Prime[Range[4 10^3]], Complement[IntegerDigits[#], {3, 4, 1}]=={} &] (* Vincenzo Librandi, Jul 26 2015 *)
  • PARI
    a(n, list=0, L=[1, 3, 4], reqpal=0)={my(t); for(d=1, 1e9, u=vector(d, i, 10^(d-i))~; forvec(v=vector(d, i, [1+(i==1&!L[1]), #L]), isprime(t=vector(d, i, L[v[i]])*u)||next; reqpal & !isprime(A004086(t)) & next; list & print1(t", "); n--||return(t)))}
    

A199342 Primes having only {2, 3, 4} as digits.

Original entry on oeis.org

2, 3, 23, 43, 223, 233, 433, 443, 2243, 2333, 2423, 3323, 3343, 3433, 4243, 4423, 22343, 22433, 23333, 24223, 24443, 32233, 32323, 32423, 32443, 33223, 33343, 42223, 42323, 42433, 42443, 43223, 222323, 223243, 223423, 224233, 224423, 224443, 232333, 232433, 233323, 233423, 234323, 234343, 242243, 243233, 243343, 243433, 244243, 244333
Offset: 1

Views

Author

M. F. Hasler, Nov 05 2011

Keywords

Comments

A020458 and A020461 are subsequences. - Vincenzo Librandi, Jul 28 2015

Crossrefs

Cf. similar sequences listed in A199340.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [3, 4, 2]]; // Vincenzo Librandi, Jul 28 2015
  • Mathematica
    Select[Prime[Range[10^5]], Complement[IntegerDigits[#], {3, 4, 2}]=={}&] (* Vincenzo Librandi, Jul 28 2015 *)
    Table[Select[FromDigits/@Tuples[{2,3,4},n],PrimeQ],{n,6}]//Flatten (* Harvey P. Dale, Nov 06 2019 *)
  • PARI
    a(n, list=0, L=[2, 3, 4], reqpal=0)={my(t); for(d=1, 1e9, u=vector(d, i, 10^(d-i))~; forvec(v=vector(d, i, [1+(i==1&!L[1]), #L]), isprime(t=vector(d, i, L[v[i]])*u)||next; reqpal & !isprime(A004086(t)) & next; list & print1(t", "); n--||return(t)))}
    

A199346 Primes having only {3, 4, 6} as digits.

Original entry on oeis.org

3, 43, 433, 443, 463, 643, 3343, 3433, 3463, 3643, 4363, 4463, 4643, 4663, 6343, 33343, 36343, 36433, 36643, 43633, 44633, 46633, 46643, 46663, 63443, 63463, 64333, 64433, 64633, 64663, 66343, 66463, 66643, 333433, 334333, 334363, 334643, 336463, 336643, 343333, 343433, 344363, 346433, 363343, 363463, 364333, 364433, 364643
Offset: 1

Views

Author

M. F. Hasler, Nov 05 2011

Keywords

Comments

All terms end in 3 and have a number of digits '4' that is not divisible by 3.
A020461 is a subsequence. - Vincenzo Librandi, Jul 29 2015

Crossrefs

Cf. similar sequences listed in A199340.

Programs

  • Magma
    [p: p in PrimesUpTo(4*10^5) | Set(Intseq(p)) subset [3, 4, 6]]; // Vincenzo Librandi, Jul 29 2015
  • Mathematica
    Select[Flatten[Table[FromDigits/@(Flatten[{#,3},1]&/@Tuples[{3,4,6},n]),{n,0,5}]],PrimeQ] (* Harvey P. Dale, Jan 01 2013 *)
    Select[Prime[Range[10^5]], Complement[IntegerDigits[#], {3, 4, 6}]=={}&] (* Vincenzo Librandi, Jul 28 2015 *)
  • PARI
    a(n, list=0, L=[3, 4, 6], reqpal=0)={my(t); for(d=1, 1e9, u=vector(d, i, 10^(d-i))~; forvec(v=vector(d, i, [1+(i==1&!L[1]), #L]), isprime(t=vector(d, i, L[v[i]])*u) || next; reqpal & !isprime(A004086(t)) & next; list & print1(t", "); n--||return(t)))}
    

A054356 The Five Hysterical Girls Theorem.

Original entry on oeis.org

3343, 33343, 333433, 334333, 333333433343
Offset: 1

Views

Author

Antti Karttunen, May 07 2000

Keywords

Comments

Mentioned in the play "The Five Hysterical Girls Theorem" by Rinne Groff at the Connelly Theater in the East Village (2000). Review: New York Times, Apr 27 2000.
The definition suggests that the sequence contains only five terms, probably randomly selected from A270338. - Arkadiusz Wesolowski, Mar 15 2016

References

  • From a posting by Adam Stephanides (adamsteph(AT)earthlink.net) to sci.math, circa May 07 2000.

Crossrefs

Cf. A020461, A036940, A138132. Subsequence of A270338.

Extensions

Broken link corrected by R. J. Mathar, Feb 05 2010

A036314 Composite numbers whose prime factors contain no digits other than 3 and 4.

Original entry on oeis.org

9, 27, 81, 129, 243, 387, 729, 1161, 1299, 1329, 1849, 2187, 3483, 3897, 3987, 5547, 6561, 10029, 10299, 10449, 11691, 11961, 16641, 18619, 19049, 19683, 30087, 30897, 31347, 35073, 35883, 49923, 55857, 57147, 59049, 79507, 90261, 92691
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

All terms are a product of at least two terms of A020461. - David A. Corneth, Oct 09 2020

Crossrefs

Formula

Sum_{n>=1} 1/a(n) = Product_{p in A020461} (p/(p - 1)) - Sum_{p in A020461} 1/p - 1 = 0.1819438988... . - Amiram Eldar, May 22 2022

A036940 Smallest n-digit prime containing only digits 3 and 4, or 0 if no such prime exists.

Original entry on oeis.org

3, 43, 433, 3343, 33343, 333433, 3333433, 34333333, 333334333, 3333334343, 33333333343, 333333343333, 3333333333433, 33333333433333, 333333333334343, 3333333333333343, 33333333333433433, 333333333333334343
Offset: 1

Views

Author

Patrick De Geest, Jan 04 1999

Keywords

Crossrefs

Programs

  • Mathematica
    Table[SelectFirst[FromDigits/@Tuples[{3,4},n],PrimeQ],{n,18}] (* The program uses the SelectFirst function from Mathematica version 10 *) (* Harvey P. Dale, May 29 2015 *)
Showing 1-10 of 13 results. Next