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.

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A354589 Primes p starting a sequence of 4 consecutive primes whose final digits are 1,3,7,9 (in any order).

Original entry on oeis.org

11, 23, 47, 53, 67, 83, 89, 101, 109, 149, 167, 191, 193, 197, 199, 211, 251, 257, 263, 383, 443, 449, 461, 487, 557, 563, 587, 593, 599, 613, 647, 659, 739, 757, 761, 821, 859, 983, 991, 1061, 1063, 1069, 1117, 1217, 1223, 1283, 1301, 1303, 1367, 1433, 1439, 1447, 1481, 1553, 1567, 1571, 1579
Offset: 1

Views

Author

J. M. Bergot and Robert Israel, Aug 18 2022

Keywords

Examples

			a(3) = 47 is in the sequence because the 4 consecutive primes starting with 47 are 47, 53, 59, 61, and their final digits 7,3,9,1 are a permutation of 1,3,7,9.
		

Crossrefs

Programs

  • Maple
    P:= select(isprime, [seq(i,i=3..2000,2)]):
    P1:= P mod 10:
    P[select(i -> convert(P1[i..i+3],set) = {1,3,7,9}, [$1..nops(P)-3])];
  • Mathematica
    Select[Partition[Prime[Range[300]], 4, 1], Sort[Mod[#, 10]] == {1, 3, 7, 9} &][[;; , 1]] (* Amiram Eldar, Aug 19 2022 *)
  • Python
    from sympy import nextprime
    from itertools import islice
    def agen(): # generator of terms
        p = [2, 3, 5, 7]
        while True:
            if set(map(lambda x: x%10, p)) == {1, 3, 7, 9}: yield p[0]
            p = p[1:] + [nextprime(p[-1])]
    print(list(islice(agen(), 60))) # Michael S. Branicky, Aug 18 2022
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