A176024 Numbers k such that the reverse concatenation of the first k integers (A000422(k)) is a prime.

82, 37765

Offset: 1

Author

Eric W. Weisstein, Apr 06 2010

Keywords

• nonn
• hard
• more
• base
• bref

Comments

a(1) was pointed out by Artur Jasinski, Mar 30 2008 (see A000422).

a(2) was found by Eric W. Weisstein, Apr 06 2010.

a(3) > 84300. - Tyler Busby, Feb 21 2023

Examples

			a(1) is 82 since the 155-digit number 828180...54321 is prime.
a(2) is 37765 since the 177719-digit number 377653776437763...54321 is (a probable) prime.
		

Links

• Eric Weisstein's World of Mathematics, Consecutive Number Sequences
• Eric Weisstein's World of Mathematics, Integer Sequence Primes
• Index entries for sequences related to Most Wanted Primes video

Crossrefs

Cf. A000422, A007908, A176942.

Extensions

Edited by N. J. A. Sloane, Dec 03 2021