OFFSET
1,1
COMMENTS
a(211) has 1008 digits. - Michael S. Branicky, Jun 23 2023
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..210
FORMULA
a(3*k) = 0. - Michael S. Branicky, Jun 23 2023
EXAMPLE
The terms of the A.P. in triangular form
2
1 3
0 0 0
1 5 9 13
3 8 13 18 23
0 0 0 0 0 0
...
Sequence contains the primes arising as a concatenation of the terms of the n-th row.
PROG
(Python)
from gmpy2 import is_prime
from itertools import count
def a(n): return next(t for t in (int("".join(str(i) for i in range(k, k+n*n, n))) for k in count(1)) if is_prime(t)) if n%3 else 0
print([a(n) for n in range(1, 19)]) # Michael S. Branicky, Jun 23 2023
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Sep 26 2003
EXTENSIONS
a(7)-a(10) from Charlie Neder, May 12 2019
a(11) and beyond from Michael S. Branicky, Jun 23 2023
STATUS
approved