OFFSET
1,1
LINKS
Indranil Ghosh, Table of n, a(n) for n = 1..10000
EXAMPLE
For n = 16, n-3 = 13. Concatenating 16 and 13 gives 1613 which is a prime. So, 1613 is in the sequence. - Indranil Ghosh, Jan 23 2017
MATHEMATICA
Select[Table[FromDigits[Join[Flatten[IntegerDigits[{n, n -3}]]]], {n, 400}], PrimeQ]
PROG
(Magma) [m: n in [4..400 by 2] | IsPrime(m) where m is Seqint(Intseq(n-3) cat Intseq(n))];
(Python)
from sympy import isprime
i=4
j=1
while j<=10000:
....if isprime(int(str(i)+str(i-3)))==True:
........print str(j)+" "+str(i)+str(i-3)
........j+=1
....i+=1 # Indranil Ghosh, Jan 23 2017
(PARI) terms(n) = my(i=0, k=3); while(i < n, my(x=eval(Str(k, k-3))); if(ispseudoprime(x), print1(x, ", "); i++); k++)
/* Print initial 35 terms as follows: */
terms(35) \\ Felix Fröhlich, Jan 23 2017
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vincenzo Librandi, Dec 08 2016
STATUS
approved