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

1,1

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

Links

Table of n, a(n) for n=1..5.

Example

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.

Sequence in context: A360930 A229080 A289270 * A343814 A106978 A260832

Adjacent sequences: A262552 A262553 A262554 * A262556 A262557 A262558

Keyword

nonn,base,more

Author

N. J. A. Sloane, Oct 09 2015

Status

approved