1,2

See A249278 and A249279 for the variant based on nonnegative integers; A162501 is a variant based not on parity but on equality.

Table of n, a(n) for n=1..77.

Index entries for sequences that are permutations of the natural numbers

(PARI) a=vector(#A249494); for(i=1, #a, A249494[i]<=#a&&a[A249494[i]]=i); a \\ Result only valid up to the first zero.

Cf. A000030, A162501.

Sequence in context: A121239 A201322 A093753 * A199046 A198564 A259072

Adjacent sequences: A249503 A249504 A249505 * A249507 A249508 A249509

nonn

M. F. Hasler, Oct 30 2014

approved