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A076586
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Total number of right truncatable primes in base n.
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15
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0, 4, 7, 14, 36, 19, 68, 68, 83, 89, 179, 176, 439, 373, 414, 473, 839, 1010, 1577, 2271, 2848, 1762, 3376, 5913, 6795, 6352, 10319, 5866, 14639, 13303, 19439, 29982, 38956, 39323, 58857, 41646, 68371, 80754, 128859, 81453, 175734, 161438, 228543, 396274, 538797
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OFFSET
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2,2
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LINKS
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Seth A. Troisi, Table of n, a(n) for n = 2..100 (terms n=2..53 from Martin Renner)
I. O. Angell and H. J. Godwin, On Truncatable Primes, Math. Comput. 31, 265-267, 1977.
Index entries for sequences related to truncatable primes
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PROG
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(Python)
from sympy import isprime, primerange
from sympy.ntheory.digits import digits
def fromdigits(digs, base):
return sum(d*base**i for i, d in enumerate(digs))
def a(n):
prime_lists, an = [(p, ) for p in primerange(1, n)], 0
digits = 1
while len(prime_lists) > 0:
an += len(prime_lists)
candidates = set((d, )+p for p in prime_lists for d in range(1, n))
prime_lists = [c for c in candidates if isprime(fromdigits(c, n))]
digits += 1
return an
print([a(n) for n in range(2, 27)]) # Michael S. Branicky, May 03 2022
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CROSSREFS
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Cf. A024763, A024764, A024765, A024766, A024767, A024768, A024769, A024770, A076623.
Sequence in context: A199628 A049945 A234576 * A240266 A064961 A137053
Adjacent sequences: A076583 A076584 A076585 * A076587 A076588 A076589
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KEYWORD
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nonn,base
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AUTHOR
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Martin Renner, Oct 20 2002, Sep 24 2007
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STATUS
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approved
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