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A053095 Number of primes having exactly the same digits as appear in first n primes. 3
1, 1, 1, 8, 62, 568, 5370, 114546, 2898058, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
COMMENTS
a(n) = 0 if sum of digits is a multiple of three (see A103208). - Ray Chandler, Apr 07 2010
LINKS
EXAMPLE
a(4)=8 because the first three prime n, concatenated, are 2+3+5+7 or 2357. There are 8 prime arrangements: 2357 2753 3257 3527 5237 5273 7253 7523.
PROG
(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
CROSSREFS
Sequence in context: A287815 A244831 A331235 * A356461 A099335 A356238
KEYWORD
base,nonn,more
AUTHOR
Enoch Haga, Mar 19 2000
EXTENSIONS
a(7)-a(9) from Ray Chandler, Apr 07 2010
a(10) from Ray Chandler, Apr 08 2010
STATUS
approved

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Last modified March 29 06:57 EDT 2024. Contains 371265 sequences. (Running on oeis4.)