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These are all composite since for prime p, ord2(p) | phi(p) = p-1, whence p mod ord2(p) = 1.
Table of n, a(n) for n=0..34.
Sequence in context: A031552 A205253 A251353 * A180651 A180331 A043444
Adjacent sequences: A036257 A036258 A036259 * A036261 A036262 A036263
David W. Wilson