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A290407
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Primes obtained from other primes by prefixing an 8.
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2
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83, 811, 823, 829, 853, 859, 883, 8101, 8167, 8179, 8191, 8233, 8263, 8269, 8293, 8311, 8317, 8353, 8389, 8419, 8431, 8443, 8461, 8467, 8521, 8563, 8599, 8641, 8647, 8677, 8719, 8761, 8821, 8839, 8863, 8887, 8929, 8941, 8971, 81013, 81019, 81031, 81049, 81097
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OFFSET
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1,1
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COMMENTS
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Except a(1), all the terms in this sequence are congruent to 1 mod 3.
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LINKS
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EXAMPLE
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823 is in the sequence because it is a prime obtained by prefixing an 8 to the prime 23.
8317 is in the sequence because it is a prime obtained by prefixing an 8 to the prime 317.
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MAPLE
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A290407:= n-> (parse(cat(8, ithprime(n)))): select(isprime, [seq((A290407 (n), n=1..1000))]);
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MATHEMATICA
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Select[k = 8; Table[FromDigits[Join[IntegerDigits[k], IntegerDigits[Prime[n]]]], {n, 500}], PrimeQ]
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PROG
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(PARI) forprime(p = 2, 5000, k=eval(concat(8, Str(p))); if(isprime(k), print1(k, ", ")));
(Magma) [k : p in PrimesUpTo (5000) | IsPrime (k) where k is Seqint (Intseq (p) cat Intseq (8))];
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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