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%I #16 Mar 23 2014 20:13:37
%S 1,2,6,71,73,114,141,147,150,192,255,480,824,871,879,1014,1270,1331,
%T 1359,1458,2244,2547,2635,3021,3447,3575,3984,4035,4138,4187,4554,
%U 6042,6419,6431,6602,6765,7074,7599,7878,8163,9768,9948,9975,10397,11572,11961,12025
%N a(n) is the minimum number greater than a(n-1) such that the concatenation a(n) U a(n-1) U ... U a(1) is a Niven number, starting with a(1)=1.
%H Paolo P. Lava and Giovanni Resta, <a href="/A239543/b239543.txt">Table of n, a(n) for n = 1..5000</a> (first 100 terms from Paolo P. Lava)
%F Starting with a(1)=1, the minimum number a(2) such that a(2) U a(1) is a Niven number is 2. In fact 21 / 3 = 7.
%F Again the minimum a(3) such that a(3) U a(2) U a(1) is a Niven number is 6. In fact 621 / 9 = 69. Etc.
%p with(numtheory);
%p S:=proc(s) local w; w:=convert(s, base, 10); sum(w[j], j=1..nops(w)); end:
%p T:=proc(t) local w,x,y; x:=t; y:=0; while x>0 do x:=trunc(x/10); y:=y+1; od; end:
%p P:=proc(q) local a,b,c,j,n; a:=1; j:=1; print(1);
%p for n from 1 to q do b:=T(a); c:=j*10^b+a;
%p if type(c/S(c),integer) then a:=j*10^b+a; print(j); fi;
%p j:=j+1; od; print(); end: P(10^6);
%Y Cf. A005349, A239542.
%K nonn,base
%O 1,2
%A _Paolo P. Lava_, Mar 21 2014
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