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A030459
Prime p concatenated with next prime is also prime.
25
2, 31, 83, 151, 157, 167, 199, 233, 251, 257, 263, 271, 331, 353, 373, 433, 467, 509, 523, 541, 601, 653, 661, 677, 727, 941, 971, 1013, 1033, 1181, 1187, 1201, 1223, 1259, 1367, 1453, 1459, 1657, 1669, 1709, 1741, 1861, 1973, 2069, 2161
OFFSET
1,1
COMMENTS
Terms 157, 257, 263, 541, 1187, 1459, 2179 also belong to A030460. - Carmine Suriano, Jan 27 2011
All terms, except for the first one, must be either in A185934 or in A185935, i.e., have the same residue (mod 6) as the subsequent prime. - M. F. Hasler, Feb 06 2011
LINKS
M. F. Hasler and Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 4110 terms from Hasler)
FORMULA
a(n) = A151799(A030460(n)).
A030461(n) = concat(a(n), A030460(n)) = A045533(A000720(a(n))).
MATHEMATICA
Select[Prime[Range[500]], PrimeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ NextPrime[#]]]]]&] (* Harvey P. Dale, Jun 20 2011 *)
PROG
(PARI) o=2; forprime(p=3, 1e4, isprime(eval(Str(o, o=p))) & print1(precprime(p-1)", ")) \\ M. F. Hasler, Feb 06 2011
CROSSREFS
See A030461 for the concatenated primes.
Sequence in context: A054207 A104095 A282725 * A141978 A212569 A101254
KEYWORD
nonn,base
STATUS
approved