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 A178466 Primes prime(k) such that the concatenation prime(k+1)//prime(k) is also prime. 0
 3, 47, 53, 61, 131, 173, 199, 211, 233, 257, 353, 523, 587, 607, 619, 647, 653, 751, 797, 971, 991, 997, 1103, 1123, 1231, 1381, 1553, 1777, 1913, 1973, 1987, 2297, 2333, 2341, 2399, 2677, 2861, 3049, 3191, 3259, 3607, 3637, 3761, 3989 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 53, 211, 653, 997, ... are also in A088712. The role of the two primes is swapped in comparison to A030459. The result of the concatenation is in A088784. LINKS FORMULA a(n) = A151799(A088712(n)). EXAMPLE The prime 53 is in the sequence because the next prime is 59 and 5953 is a prime. MAPLE read("transforms") ; for n from 1 to 600 do p := ithprime(n) ; q := nextprime(p) ; r := digcat2(q, p) ; if isprime(r) then printf("%d, ", p) ; end if; end do: # R. J. Mathar, Jan 27 2011 MATHEMATICA Transpose[Select[Partition[Prime[Range[600]], 2, 1], PrimeQ[FromDigits[ Flatten[ IntegerDigits/@Reverse[#]]]]&]][[1]]  (* Harvey P. Dale, Feb 02 2011 *) CROSSREFS Cf. A030459, A030460, A088712. Sequence in context: A260882 A128109 A159246 * A227171 A055058 A139845 Adjacent sequences:  A178463 A178464 A178465 * A178467 A178468 A178469 KEYWORD nonn,base AUTHOR Carmine Suriano, Jan 27 2011 STATUS approved

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Last modified August 10 12:19 EDT 2020. Contains 336379 sequences. (Running on oeis4.)