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 A178553 Primes with exactly four 4's. 5
 44449, 404449, 440441, 440443, 441443, 441449, 442447, 444043, 444047, 444341, 444343, 444347, 444349, 444401, 444403, 444421, 444461, 444463, 444469, 444473, 444487, 444547, 444641, 444649, 444841, 445447, 446441, 446447, 447443, 447449, 449441 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Daniel Starodubtsev, Table of n, a(n) for n = 1..10000 PROG (PARI) isok(p) = isprime(p) && (#select(x->(x==4), digits(p)) == 4); \\ Michel Marcus, Mar 15 2020 CROSSREFS Cf. A038618, A178550, A178551, A178552, A178554, A178555, A178556, A178557, A178558. Sequence in context: A115959 A045937 A138359 * A216203 A194355 A258514 Adjacent sequences:  A178550 A178551 A178552 * A178554 A178555 A178556 KEYWORD nonn,base AUTHOR Lekraj Beedassy, May 29 2010 EXTENSIONS Missing a(13) = 444349 inserted by Daniel Starodubtsev, Mar 15 2020 STATUS approved

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Last modified June 22 04:06 EDT 2021. Contains 345367 sequences. (Running on oeis4.)