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A163760 Exactly four distinct primes occur as substrings of the digits of n. 1
113, 131, 179, 197, 223, 231, 233, 235, 239, 253, 257, 271, 273, 283, 293, 297, 311, 313, 337, 347, 353, 359, 367, 371, 372, 375, 397, 431, 437, 473, 479, 531, 532, 547, 571, 573, 593, 597, 613, 617, 653, 713, 719, 723, 731, 732, 733, 735, 737, 739, 743 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 10*n, 10*n+4, 10*n+6 and 10*n+8 are all in the sequence if any one of them is. - Robert Israel, Mar 21 2019

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

a(1) = 113 because "3" and "11" and "13" and "113" are prime substrings of "113".

MAPLE

filter:= proc(n) local L, m, SS, S, count, i, j;

  L:= convert(n, base, 10);

  m:= nops(L);

  SS:= remove(t -> t[-1]=0, {seq(seq(L[i..j], j=i..m), i=1..m)});

  nops(select(isprime, map(S -> add(S[i]*10^(i-1), i=1..nops(S)), SS))) = 4

end proc:

select(filter, [$100..1000]); # Robert Israel, Mar 21 2019

CROSSREFS

Cf. A163754, A163759.

Sequence in context: A131648 A180441 A180407 * A179911 A344627 A187867

Adjacent sequences:  A163757 A163758 A163759 * A163761 A163762 A163763

KEYWORD

base,easy,nonn

AUTHOR

Gil Broussard, Aug 03 2009

STATUS

approved

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Last modified July 25 16:39 EDT 2021. Contains 346291 sequences. (Running on oeis4.)