1,1

Table of n, a(n) for n=1..6.

Makoto Kamada, Prime numbers of the form 22...223.

Index entries for primes involving repunits

a(n) = (20*10^A056656(n) + 7)/9 = (2*10^A096506(n) + 7)/9.

Cf. A002275, A056656 (corresponding n, and count of digits 2 in a(n)), A096506.

Sequence in context: A093135 A305754 A202997 * A328808 A206763 A306154

Adjacent sequences: A093159 A093160 A093161 * A093163 A093164 A093165

nonn

Rick L. Shepherd, Mar 26 2004

Edited by Ray Chandler, Feb 27 2012

approved