A098144 a(n) = smallest number greater than a(n-1) having a largest proper divisor that is greater than and coprime to a(n-1); a(1) = 1.

1, 4, 9, 10, 21, 22, 39, 40, 63, 64, 99, 100, 153, 154, 237, 238, 363, 364, 549, 550, 831, 832, 1251, 1252, 1881, 1882, 2829, 2830, 4251, 4252, 6381, 6382, 9579, 9580, 14373, 14374, 21567, 21568, 32355, 32356, 48537, 48538, 72813, 72814, 109227, 109228

Offset

1,2

Comments

A032742(a(n+1))>A032742(a(n)) and GCD(A032742(a(n+1)), A032742(a(n)))=1;

for n>1: a(2*n) = a(2*n-1) + 1,

a(2*n+1) = 3*(a(2*n)/2 + 2 - 0^(a(2*n) mod 4)).

Links

Table of n, a(n) for n=1..46.

Crossrefs

Sequence in context: A338906 A367855 A107621 * A109412 A061766 A109448

Adjacent sequences: A098141 A098142 A098143 * A098145 A098146 A098147

Keyword

nonn

Author

Reinhard Zumkeller, Sep 28 2004

Status

approved