A225234 Primes whose internal digits are an emirp.

1171, 1319, 1373, 1733, 1973, 1979, 2131, 2137, 2179, 2311, 2371, 2377, 2711, 2713, 2719, 2731, 2791, 2797, 2971, 3137, 3313, 3319, 3371, 3373, 3719, 3733, 3739, 3793, 3797, 4133, 4139, 4177, 4373, 4733, 4793, 4799, 4973, 5171, 5179, 5711, 5717, 5737, 5791

Offset

1,1

Comments

a(414) = 112019 is the first term with an internal even digit.

Links

Christian N. K. Anderson, Table of n, a(n) for n = 1..10000

Example

Example: 1171 has the emirp 17 as its internal digits.

Prog

(R) library(gmp); isemirp<-function(x) isprime(x) & (j=paste(rev(unlist(strsplit(as.character(x), split=""))), collapse=""))!=x & isprime(j);
no0<-function(s){ while(substr(s, 1, 1)=="0" & nchar(s)>1) s=substr(s, 2, nchar(s)); s}
i=as.bigz(0); y=as.bigz(rep(0, 100)); len=0;
while(len<100) if(isemirp(as.bigz(no0(substr((i=nextprime(i)), 2, nchar(as.character(i))-1))))) y[(len=len+1)]=i

Crossrefs

Cf. A210498, A006567, A024770, A000040, A225235, A214847.

Sequence in context: A065703 A202487 A230946 * A253508 A235206 A302230

Adjacent sequences: A225231 A225232 A225233 * A225235 A225236 A225237

Keyword

nonn,base,less

Author

Kevin L. Schwartz and Christian N. K. Anderson, May 03 2013

Status

approved