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A068838
Smallest prime with concatenation of first n even numbers as leading digits.
2
2, 241, 2467, 24683, 2468101, 246810121, 24681012149, 24681012141601, 2468101214161811, 246810121416182039, 24681012141618202211, 2468101214161820222441, 246810121416182022242641, 246810121416182022242628043, 24681012141618202224262830073
OFFSET
1,1
COMMENTS
a(350) has 1001 digits. - Michael S. Branicky, Mar 19 2024
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..349 (terms 1..300 from Harvey P. Dale with corrections to terms 1..175 by Sean A. Irvine and corrections in 176..300 by Michael S. Branicky)
PROG
(Python)
from sympy import isprime
from itertools import count
def a(n):
if n == 1: return 2
prefix = int("".join(map(str, (2*i for i in range(1, n+1)))))
for extra in count(1):
prefix *= 10
for i in range(10**extra):
t = prefix + i
if isprime(t): return t
print([a(n) for n in range(1, 16)]) # Michael S. Branicky, Mar 19 2024
CROSSREFS
Sequence in context: A006523 A294319 A055968 * A074256 A146312 A109930
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Mar 09 2002
EXTENSIONS
More terms from Benoit Cloitre, Mar 10 2002
Corrected by T. D. Noe, Nov 15 2006
Corrected and extended by Jayanta Basu, Aug 09 2013
Data corrected by Sean A. Irvine, Mar 19 2024
STATUS
approved