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A069588
Smallest prime in which the n-th significant digit is a 1.
10
11, 11, 101, 1009, 10007, 100003, 1000003, 10000019, 100000007, 1000000007, 10000000019, 100000000003, 1000000000039, 10000000000037, 100000000000031, 1000000000000037, 10000000000000061, 100000000000000003, 1000000000000000003, 10000000000000000051
OFFSET
1,1
COMMENTS
Essentially (i.e., except for the initial term), the same as A003617. The definition is misleading, since "n-th significant digit" seems to mean here "most significant digit" (except for a(1)), while the "significance" is decreasing when going from the first to the last digit. (E.g., 1234 rounded to 2 significant digits is 1200, so "1,2" should be the first and second (and not fourth and third) significant digits.) [M. F. Hasler, Jun 03 2009]
LINKS
MAPLE
11, seq(nextprime(10^j), j=1..30);
MATHEMATICA
Join[{11}, NextPrime[10^Range[20]]] (* Paolo Xausa, Jun 23 2024 *)
PROG
(Python)
from sympy import nextprime
def a(n): return 11 if n == 1 else nextprime(10**(n-1))
print([a(n) for n in range(1, 21)]) # Michael S. Branicky, Nov 11 2021
CROSSREFS
Sequence in context: A088772 A088771 A088773 * A088774 A255745 A188548
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Mar 25 2002
EXTENSIONS
More terms from Sascha Kurz, Mar 28 2002
a(19) and beyond from Michael S. Branicky, Nov 11 2021
STATUS
approved