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 A280376 Primes formed from the concatenation of n and nextprime(n). 1
 23, 67, 811, 911, 1213, 2729, 3137, 3637, 4243, 4447, 4547, 5153, 5659, 6367, 6871, 6971, 7879, 8389, 8689, 9397, 9497, 9697, 98101, 102103, 104107, 105107, 108109, 115127, 117127, 118127, 123127, 126127, 132137, 138139, 150151, 151157, 154157, 156157, 157163 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS K. D. Bajpai, Table of n, a(n) for n = 1..10000 EXAMPLE 811 is in the sequence because it is prime formed from the concatenation of 8 and 11, where 11 is the prime next to 8. 3137 is in the sequence because it is prime formed from the concatenation of 31 and 37, where 37 is the prime next to 31. MAPLE f:= proc(n) local x, p;    p:= nextprime(n);    x:= n*10^(1+ilog10(p))+p;    if isprime(x) then x else NULL fi end proc: map(f, [\$1..200]); # Robert Israel, Jan 01 2017 MATHEMATICA Select[Table[FromDigits[Join[IntegerDigits[n], IntegerDigits[NextPrime[n]]]], {n, 500}], PrimeQ] PROG (Magma) [p : n in[1 .. 200] | IsPrime (p) where p is Seqint(Intseq (NextPrime(n)) cat Intseq(n))]; CROSSREFS Cf. A084667, A084669, A151800. Subsequence of primes of A049852. Sequence in context: A142302 A276262 A078622 * A134428 A195039 A042036 Adjacent sequences:  A280373 A280374 A280375 * A280377 A280378 A280379 KEYWORD nonn,base AUTHOR K. D. Bajpai, Jan 01 2017 STATUS approved

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Last modified October 19 11:09 EDT 2019. Contains 328216 sequences. (Running on oeis4.)