|
%I #9 Sep 05 2013 07:46:32
%S 1,5,15,25,29,35,125,625,2125,2675,3125,15625,20125,21875,23975,24797,
%T 25125,36875,47495,47725,51875,53125,78125,135475,390625,1171875,
%U 1903875,1928595,2142375,2265625,6617125,8385625,8790525,8807085,8818575,10504785
%N Smallest odd number greater than any previous term such that it divides the concatenation of all the previous terms and itself; begin with 1.
%C Terms not congruent to 0 (mod 5) are: 1, 29, 24797, 24848081, 91381387, 274144161, ..., .
%C Terms not congruent to 0 (mod 25) are: 1, 5, 15, 29, 35, 24797, 47495, 1928595, 8807085, 10504785, 24848081, 91381387, 274144161, ..., .
%H Robert G. Wilson v, <a href="/A228806/b228806.txt">Table of n, a(n) for n = 1..55</a>
%e a(5) equals 29 because 15152527 (mod 27) == 19, but 15152529 (mod 29) == 0.
%t f[s_List] := Block[{k = s[[-1]] + 2, conc = FromDigits[ Flatten@ IntegerDigits@ s]}, While[ Mod[ conc*10^Floor[ Log[10, k] + 1] + k, k] != 0, k += 2]; Append[s, k]]; Nest[f, {1}, 25]
%Y Cf. A171785.
%K nonn,base
%O 1,2
%A _Robert G. Wilson v_, Sep 04 2013
|
