%I #6 Jan 17 2015 12:23:23
%S 0,1,2,18,3,70,39,75,10,193,16,85,124,23,51,200,20,79,41,303,28,102,
%T 98,1105,71,115,73,301,543,152,325,344,15,64,27,125,47,66,170,179,306,
%U 93,289,1174,49,376,1195,440,45,566,312,1170,104,2133,108,468,162
%N Smallest number m such that A253581(m) = n.
%C A253581(a(n)) = n; conjecture: the sequence is defined for all n.
%H Reinhard Zumkeller, <a href="/A253603/b253603.txt">Table of n, a(n) for n = 0..1000</a>
%o (Haskell)
%o import Data.List (elemIndex); import Data.Maybe (fromJust)
%o a253603 = fromJust . (`elemIndex` a253581_list)
%Y Cf. A253581, A252867.
%K nonn
%O 0,3
%A _Reinhard Zumkeller_, Jan 12 2015