A143051 - OEIS

A143051

Smallest number not occurring earlier and smaller than the largest square so far, the next square if no such number exists.

0, 1, 4, 2, 3, 9, 5, 6, 7, 8, 16, 10, 11, 12, 13, 14, 15, 25, 17, 18, 19, 20, 21, 22, 23, 24, 36, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 49, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 64, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 81, 65, 66, 67, 68, 69, 70, 71

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OFFSET

0,3

COMMENTS

Permutation of the natural numbers, inverse: A143052;

A143053(n) = a(a(n));

a(A000290(n)) = A005563(n-1);

a(A002522(n)) = A000290(n+1);

for n>1: GCD(a(n^2),a(n^2+1)) = A050873(A000290(n),A002522(n)) =

A022998(n+1).

LINKS

Peter Kagey, Table of n, a(n) for n = 0..10000