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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.)