1,7

See A157017 for examples and references.

Table of n, a(n) for n=1..82.

Sequence in context: A030347 A010275 A176494 * A242248 A107297 A107296

Adjacent sequences: A157226 A157227 A157228 * A157230 A157231 A157232

nonn

T. D. Noe, Feb 25 2009; extended Feb 27 2009 with help from Ray Chandler

approved