A178554 Primes with exactly five 5's.

555557, 1555553, 2555551, 3555551, 3555557, 4555559, 5055551, 5055559, 5355551, 5505551, 5535559, 5550553, 5550557, 5554553, 5555057, 5555059, 5555357, 5555507, 5555509, 5555527, 5555567, 5555591, 5555653, 5556557, 5556559, 5557553

Offset: 1

Author

Lekraj Beedassy, May 29 2010

Keywords

• nonn
• base

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A038618, A178550, A178551, A178552, A178553, A178555, A178556, A178557, A178558.

Programs

Mathematica

Select[Prime[Range[PrimePi[55555],1000000]],Count[IntegerDigits[#],5]==5&]  (* Harvey P. Dale, Dec 20 2010 *)

PARI

isok(p) = isprime(p) && (#select(x->(x==5), digits(p)) == 5); \\ Michel Marcus, Mar 15 2020

Extensions

Missing a(14) = 5554553 inserted by Daniel Starodubtsev, Mar 15 2020