OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
FORMULA
a(n) ~ n log n. - Charles R Greathouse IV, Aug 29 2015
MATHEMATICA
Select[Prime[Range[205]], MemberQ[Differences[IntegerDigits[#]], 0]&] (* Jayanta Basu, May 31 2013 *)
Select[Prime[Range[300]], SequenceCount[IntegerDigits[#], {x_, x_}]>0&] (* The program uses the SequenceCount function from Mathematica version 10 *) (* Harvey P. Dale, Feb 20 2016 *)
PROG
(PARI) is(n)=my(d=digits(n)); for(i=2, #d, if(d[i]==d[i-1], return(isprime(n)))); 0 \\ Charles R Greathouse IV, Aug 29 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest, Sep 15 1999
STATUS
approved