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 1-3 of 3 results.

A253574 Primes p such that digits of p do not appear in p^4.

Original entry on oeis.org

2, 3, 7, 53, 59, 67, 89, 383, 887, 2027, 3253, 5669, 7993, 8009, 9059, 53633, 54667, 56533, 88883, 272777777, 299222299, 383833883, 797769997
Offset: 1

Views

Author

Vincenzo Librandi, Jan 04 2015

Keywords

Comments

Primes in A111116.
No further terms up to 10^9. - Felix Fröhlich, Jan 04 2015
No further terms up to 10^10. - Chai Wah Wu, Jan 06 2015
No further terms up to 2.5*10^13 - Giovanni Resta, Jun 01 2015
No further terms up to 10^19 (via A111116). - Michael S. Branicky, Jan 05 2022

Examples

			2 and 2^4=16 have no digits in common, hence 2 is in the sequence.
		

Crossrefs

Cf. A111116.
Cf. primes such that digits of p do not appear in p^k: A030086 (k=2), A030087 (k=3), this sequence (k=4), no terms (k=5), A253575 (k=6), A253576 (k=7), A253577 (k=8), no terms (k=9), A253578 (k=10).

Programs

  • Mathematica
    Select[Prime[Range[1000000]], Intersection[IntegerDigits[#], IntegerDigits[#^4]]=={} &]
  • PARI
    forprime(p=1, 1e9, dip=digits(p); dipf=digits(p^4); sharedi=0; for(i=1, #dip, for(j=1, #dipf, if(dip[i]==dipf[j], sharedi++; break({2})))); if(sharedi==0, print1(p, ", "))) \\ Felix Fröhlich, Jan 04 2015
    
  • Python
    from sympy import isprime
    A253574_list = [n for n in range(1,10**6) if set(str(n)) & set(str(n**4)) == set() and isprime(n)]
    # Chai Wah Wu, Jan 06 2015

Extensions

a(20)-a(23) from Felix Fröhlich, Jan 04 2015

A030087 Primes such that digits of p do not appear in p^3.

Original entry on oeis.org

2, 3, 7, 43, 47, 53, 157, 223, 263, 487, 577, 587, 823, 4657, 5657, 6653, 7177, 8287, 9343, 26777, 36293, 46477, 58787, 72727, 75707, 176777, 363313, 530353, 566653, 959953, 1771787, 2525557, 2555353, 2626277, 3656363, 4414447, 7110707, 8448343, 20700077, 54475457, 71117177, 72722977, 135135113, 393321293, 457887457, 505053053, 672722627
Offset: 1

Views

Author

Patrick De Geest, Dec 11 1999

Keywords

Comments

Primes of sequence A029785. - Michel Marcus, Jan 04 2015

Examples

			2 and 2^3=8 have no digits in common, hence 2 is in the sequence.
		

Crossrefs

Cf. A029785 (digits of n are not present in n^3), A030086 (similar, with p^2), A253574 (similar, with p^4).

Programs

  • Mathematica
    Select[Prime[Range[1500000]], Intersection[IntegerDigits[#], IntegerDigits[#^3]]=={} &] (* Vincenzo Librandi, Jan 04 2015 *)
  • PARI
    lista(nn) = {forprime (n=1, nn, if (#setintersect(Set(vecsort(digits(n^3))), Set(vecsort(digits(n)))) == 0, print1(n, ", ")); ); } \\ Michel Marcus, Jan 04 2015
    
  • Python
    from sympy import isprime
    A030087_list = [n for n in range(1,10**6) if set(str(n)) & set(str(n**3)) == set() and isprime(n)]
    # Chai Wah Wu, Jan 05 2015

Extensions

Changed offset from 0 to 1 and more terms from Vincenzo Librandi, Jan 04 2015
a(40)-a(47) from Chai Wah Wu, Jan 05 2015

A030088 a(n) = prime^2 and digits of prime do not appear in a(n).

Original entry on oeis.org

4, 9, 49, 289, 841, 2209, 2809, 3481, 4489, 6241, 24649, 29929, 66049, 94249, 97969, 121801, 124609, 128881, 167281, 201601, 218089, 299209, 310249, 332929, 434281, 452929, 458329, 546121, 619369, 727609, 863041, 2093809
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A030086.
Subsequence of A001248.

Programs

  • Maple
    R:= NULL: count:= 0: p:= 0:
    while count < 40 do
      p:= nextprime(p);
      ps:= p^2;
      if convert(convert(p,base,10),set) intersect convert(convert(ps,base,10),set) = {} then
        R:= R, ps; count:= count+1
      fi
    od:
    R; # Robert Israel, Nov 02 2022
  • Mathematica
    Select[Prime[Range[250]],Intersection[IntegerDigits[#],IntegerDigits[#^2]]=={}&]^2 (* Harvey P. Dale, May 18 2024 *)

Formula

a(n) = A030086(n)^2. - Robert Israel, Nov 02 2022
Showing 1-3 of 3 results.