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A057706
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Smaller of twin primes whose average is a primorial number.
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5
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OFFSET
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1,1
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COMMENTS
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According to Caldwell, the next term, if it exists, has more than 100000 digits. - T. D. Noe, May 08 2012
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LINKS
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Table of n, a(n) for n=1..3.
Chris K. Caldwell, Primorial prime.
Rudolf Ondrejka, The Top Ten: a Catalogue of Primal Configurations, 2001, tables 20A, 20B.
Eric Weisstein's World of Mathematics, Primorial Prime.
Index entries for sequences related to primorial numbers.
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EXAMPLE
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(5+7)/2 = 6 = 2*3, (29+31)/2 = 30 = 2*3*5, (2309+2311)/2 = 2310 = 2*3*5*7*11.
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MATHEMATICA
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Select[FoldList[Times, Prime@ Range@ 40], AllTrue[# + {-1, 1}, PrimeQ] &] - 1 (* Michael De Vlieger, Jul 15 2017 *)
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CROSSREFS
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Cf. A000040 (primes), A002110 (primorials, p#).
Cf. A006862 (Euclid, p#+1), A005234 (prime p#+1), A014545 (index prime p#+1).
Cf. A057588 (Kummer, p#-1), A006794 (prime p#-1), A057704 (index prime p#-1).
Sequence in context: A057208 A046842 A175905 * A057705 A237188 A086720
Adjacent sequences: A057703 A057704 A057705 * A057707 A057708 A057709
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KEYWORD
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nonn,bref
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AUTHOR
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Labos Elemer, Oct 24 2000
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EXTENSIONS
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Offset corrected by Arkadiusz Wesolowski, May 08 2012
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STATUS
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approved
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