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.

A052042 Primes that lack the digit zero in the decimal expansion of their squares.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 59, 61, 67, 73, 79, 83, 89, 107, 109, 113, 127, 131, 137, 139, 157, 163, 167, 173, 181, 191, 193, 211, 223, 227, 229, 233, 239, 263, 269, 271, 277, 281, 293, 307, 311, 313, 337, 359, 367, 373, 379, 383, 389, 409, 419, 421, 431
Offset: 1

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Author

Patrick De Geest, Dec 15 1999

Keywords

Examples

			The primes 47, 53 and 71 are not in the sequence because 47^2=2209, 53^2=2809 and 71^2=5041 contain zeros in their decimal representation.
		

Crossrefs

Programs

  • Mathematica
    fQ[n_] := DigitCount[n^2][[-1]] == 0; Select[Prime@ Range@ 80, fQ] (* Robert G. Wilson v, Aug 22 2012 *)
  • PARI
    {p=2;for(k=1,10^2,if(vecmin(digits(p^2))>0,
    print1(p", "));p=nextprime(1+p))}\\ Zak Seidov, Dec 24 2014

Formula

a(n) = sqrt(A052043(n)). - Zak Seidov, Dec 27 2014