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.

A231588 Primes with decimal digits in arithmetic progression mod 10.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 109, 173, 197, 307, 383, 593, 727, 739, 937, 2963, 4567, 4703, 5791, 7159, 8147, 9371, 10987, 15937, 19753, 37159, 52963, 53197, 58147, 71593, 72727, 73951, 76543
Offset: 1

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Author

Paul Tek, Nov 11 2013

Keywords

Comments

This sequence contains straight-line primes (A167847).
a(216) has 1012 digits. - Michael S. Branicky, Aug 05 2022

Examples

			(7,2,7,2,7,...) is an arithmetic progression mod 10, hence the prime number 72727 appears in this sequence.
(7,6,5,4,3,...) is an arithmetic progression mod 10, hence the prime number 76543 appears in this sequence.
		

Crossrefs

Cf. A167847.

Programs

  • Mathematica
    Select[Prime[Range[PrimePi[76543]]], Length[Union[Mod[Differences[IntegerDigits[#]], 10]]] <= 1 &]
  • PARI
    See Link section.
    
  • Python
    from sympy import isprime
    from itertools import count, islice
    def bgen():
        yield from [2, 3, 5, 7]
        yield from (int("".join(str((s0+i*r)%10) for i in range(d))) for d in count(2) for s0 in range(1, 10) for r in range(-s0, 10-s0))
    def agen(): yield from filter(isprime, bgen())
    print(list(islice(agen(), 52))) # Michael S. Branicky, Aug 05 2022