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A121815 Least positive k such that (n*10^n+n+1)*10^n+k is prime. 0
7, 23, 13, 29, 3, 7, 29, 57, 3, 43, 21, 69, 31, 9, 19, 31, 179, 21, 167, 71, 19, 13, 3, 207, 29, 89, 123, 343, 171, 73, 127, 171, 9, 329, 101, 463, 373, 9, 87, 77, 33, 661, 493, 159, 159, 89, 417, 21, 269, 381, 181, 421, 219, 183, 173, 357, 21, 13, 293, 109, 1187, 77 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Note that a(87)=87; any more where k=n?
LINKS
EXAMPLE
a(5)=3 because 50000600003 is prime.
CROSSREFS
Sequence in context: A367003 A167224 A175483 * A025172 A115023 A009228
KEYWORD
nonn
AUTHOR
Jason Earls, Aug 26 2006
STATUS
approved

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Last modified April 21 07:37 EDT 2024. Contains 371850 sequences. (Running on oeis4.)