A262555 Numbers n such that the concatenation of the decimal numbers 1 through n, but omitting 2, is a prime.

3, 41, 103, 1713, 2769

Offset: 1

Author

N. J. A. Sloane, Oct 09 2015

Keywords

• nonn
• base
• more

Comments

The corresponding primes are the primes in A262572. Probabilistic arguments suggest the sequence is infinite.

a(6) > 10000, if it exists. - Robert Price, Nov 04 2018

Examples

			The first two terms correspond to the primes 13 and 134567891011121314151617181920212223242526272829303132333435363738394041 (see A262298).
a(3) corresponds to a prime ending in 103, with 200 digits, a(4) to  a probable prime ending in 1713, with 5744 digits, and a(5) to a probable prime ending in 2769, with 9968 digits. These three terms were found by _David Broadhurst_ on Oct 09 2015.
		

Crossrefs

Cf. A262572, A262298, A007908.