A239236 Numbers n such that d_1^n + d_2^n + ... + d_k^n is prime where d_i represents the i-th digit in the decimal representation of n.

11, 101, 110, 111, 353, 1001, 1010, 1011, 1100, 1101, 1110, 10001, 10010, 10011, 10100, 10101, 10110, 11000, 11001, 11010, 11100, 11111, 62315, 100001, 100010, 100011, 100100, 100101, 100110, 101000, 101001, 101010, 101100, 101111, 110000, 110001, 110010

Offset

1,1

Comments

The terms in A007088 with a prime number of 1's are trivially contained in this sequence.

Links

Table of n, a(n) for n=1..37.

Example

1011 is a member of this sequence because 1^1011 + 0^1011 + 1^1011 + 1^1011 = 3 is prime.

Prog

(Python)
import sympy
from sympy import isprime
def Pow(x):
..num = 0
..for i in str(x):
....num += int(i)**x
..if isprime(num):
....return True
x = 1
while x < 10**5:
..if Pow(x):
....print(x)
..x += 1

Crossrefs

Cf. A007088, A239237.

Sequence in context: A245475 A175963 A359610 * A043494 A277959 A278937

Adjacent sequences: A239233 A239234 A239235 * A239237 A239238 A239239

Keyword

nonn,base

Author

Derek Orr, Mar 13 2014

Extensions

a(12)-a(37) from Giovanni Resta, Mar 14 2014

Status

approved