1,3

Table of n, a(n) for n=1..73.

comp(n(n+1)/2) - comp(n(n-1)/2), where comp(m) = number of composite numbers less than or equal to m.

a(5) = 3, among 11,12,13,14,15 there are three composite numbers 12,14 and 15.

Cf. A093004.

Sequence in context: A239964 A290585 A106464 * A118096 A296440 A181692

Adjacent sequences: A093000 A093001 A093002 * A093004 A093005 A093006

nonn

Amarnath Murthy, Mar 29 2004

Corrected and extended by Joshua Zucker, May 08 2006

approved