A349732 - OEIS

%I #8 Nov 28 2021 12:59:47

%S 1,2,3,4,5,6,7,8,9,19,0,24,0,25,32,26,0,27,0,28,34,29,0,35,50,0,36,43,

%T 0,37,0,44,38,0,52,39,0,0,0,46,0,61,0,47,54,0,0,48,70,55,0,49,0,63,56,

%U 71,0,0,0,57,0,0,72,80,58,65,0,0,0,59,0,66,0,0,0,0,74,67,0,82,90

%N Smallest k such that A349194(k) = n, or 0 if no such k exists.

%C Composite numbers m for which a(m) = 0 are in A349733.

%F If p prime >= 11, a(p) = 0.

%e a(10) = 19 since 1*(1+9) = 10 and no integer du < 19 gives d*(d+u) = 10.

%Y Cf. A349194, A349733.

%K nonn,base

%O 1,2

%A _Bernard Schott_, Nov 28 2021