OFFSET
1,1
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..10000
EXAMPLE
409 is a prime number whose first digit is 4, a composite number, so 409 is a term.
MAPLE
KD := proc() local a, b, d, e; a:= ithprime(n); b:=length(a); d:=a/(10^(b-1)); e:=floor(d); if isprime(e)=false and e>1 then RETURN (a): fi; end: seq(KD(), n=1..200);
PROG
(Python)
from sympy import primerange
from itertools import count, islice
def agen(): yield from (p for e in count(1) for k in [4, 6, 8, 9] for p in primerange(k*10**e, (k+1)*10**e))
print(list(islice(agen(), 54))) # Michael S. Branicky, Jun 25 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
K. D. Bajpai, Aug 24 2013
STATUS
approved