2,1

Table of n, a(n) for n=2..8.

The earliest chain of 4 consecutive primes separated by gaps 2^1, 2^2, 2^3 is: 1997, 1999, 2003, 2011. Hence a(4) = 1997.

Cf. A079014.

Sequence in context: A298094 A012783 A062655 * A138154 A333269 A319598

Adjacent sequences: A090804 A090805 A090806 * A090808 A090809 A090810

nonn

Joseph L. Pe, Feb 12 2004

a(7)-a(8) from Donovan Johnson, Mar 23 2013

approved