A329764 - OEIS

%I #8 Dec 16 2019 20:09:18

%S 1,3,15,75,375,9375,159375,71559375,1195399359375,353915911333359375,

%T 51915571117579153359375,753315397517553377717399173359375,

%U 3319771735775931191533111595353537393933359375

%N a(1) = 1; thereafter a(n+1) > a(n) is the smallest multiple of a(n) using only odd digits but not divisible by 9.

%C Equivalently, the sequence is defined as a(1) = 1, a(2) = 3, a(3) = 15, and for n > 2, a(n+1) > a(n) is the smallest multiple of a(n) using only odd digits. All terms besides a(1) and a(2) are divisible by 5.

%Y Cf. A329762, A078221, A078223.

%K nonn,base

%O 1,2

%A _Chai Wah Wu_, Dec 04 2019