1,1

Primes start with 1, then, after (n-4) 0's, end with 1111.

n=5: 101111 is prime, n=11: 100000001111 is prime.

Sequence in context: A131898 A069097 A024921 this_sequence A161896 A167610 A143127

Adjacent sequences: A152530 A152531 A152532 this_sequence A152534 A152535 A152536

nonn

Zak Seidov (zakseidov(AT)yahoo.com), Dec 06 2008