A053095 Number of primes having exactly the same digits as appear in first n primes.
1, 1, 1, 8, 62, 568, 5370, 114546, 2898058, 0, 1119268465, 26053674813
Offset: 1
Examples
a(4) = 8 because the first four prime n, concatenated, are 2+3+5+7 or 2357. There are 8 prime arrangements: 2357, 2753, 3257, 3527, 5237, 5273, 7253, 7523.
Programs
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Python
from sympy import isprime, prime from sympy.utilities.iterables import multiset_permutations def A053095(n): return sum(1 for d in multiset_permutations(''.join(str(prime(m+1)) for m in range(n))) if isprime(int(''.join(d)))) # Chai Wah Wu, Mar 17 2019
Extensions
a(7)-a(9) from Ray Chandler, Apr 07 2010
a(10) from Ray Chandler, Apr 08 2010
a(11) from Michael S. Branicky, Mar 17 2025
a(12) from Michael S. Branicky, Apr 07 2025
Comments