A178550 Primes with exactly one digit 1.

13, 17, 19, 31, 41, 61, 71, 103, 107, 109, 127, 137, 139, 149, 157, 163, 167, 173, 179, 193, 197, 199, 241, 251, 271, 281, 313, 317, 331, 401, 419, 421, 431, 461, 491, 521, 541, 571, 601, 613, 617, 619, 631, 641, 661, 691, 701, 719, 751, 761, 821, 881, 919, 941, 971, 991

Offset: 1

Author

Lekraj Beedassy, May 29 2010

Keywords

• nonn
• base
• changed

Links

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

Crossrefs

Intersection of A043493 and A000040.

Cf. A038618, A178551, A178552, A178553, A178554, A178555, A178556, A178557, A178558.

Programs

Mathematica

Select[Prime[Range[200]],Count[IntegerDigits[#],1]==1 &] (* Stefano Spezia, Aug 29 2025 *)

Python

from sympy import isprime
print([i for i in range(1000) if str(i).count('1') == 1 and isprime(i)]) # Daniel Starodubtsev, Mar 29 2020

Formula

a(n) >> n^k where k = log(10)/log(9) = 1.04795.... - Charles R Greathouse IV, Jan 21 2025