A069592 Smallest prime in which the n-th significant digit is a 5.

5, 53, 503, 5003, 50021, 500009, 5000011, 50000017, 500000003, 5000000029, 50000000021, 500000000023, 5000000000053, 50000000000053, 500000000000057, 5000000000000023, 50000000000000051, 500000000000000021

Offset: 1

Author

Amarnath Murthy, Mar 25 2002

Keywords

• base
• nonn

Links

• Abhiram R Devesh, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A069588, A069589, A069590, A069591.

Programs

Maple

5,seq(nextprime(5*10^j),j=1..32);

Mathematica

a069592[n_Integer] := Module[{f}, f[1] = 5; f[i_] := NextPrime[5*10^(i - 1)]; f[n]]; Map[a069592, Range[100]] (* Michael De Vlieger, Aug 06 2014 *)
Join[{5},NextPrime[5*10^Range[20]]] (* Harvey P. Dale, May 15 2016 *)

PARI

a(n) = nextprime(5*10^n); \\ Michel Marcus, Aug 07 2014

Python

import sympy
i=0
print(5)
i=i+1
while i > -1:
    a=5*(10**i)
    p=sympy.nextprime(a)
    print(p)
    i=i+1
## Abhiram R Devesh, Jul 31 2014

Extensions

More terms from Sascha Kurz, Mar 28 2002