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 A228806 Smallest odd number greater than any previous term such that it divides the concatenation of all the previous terms and itself; begin with 1. 1
 1, 5, 15, 25, 29, 35, 125, 625, 2125, 2675, 3125, 15625, 20125, 21875, 23975, 24797, 25125, 36875, 47495, 47725, 51875, 53125, 78125, 135475, 390625, 1171875, 1903875, 1928595, 2142375, 2265625, 6617125, 8385625, 8790525, 8807085, 8818575, 10504785 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Terms not congruent to 0 (mod 5) are: 1, 29, 24797, 24848081, 91381387, 274144161, ..., . Terms not congruent to 0 (mod 25) are: 1, 5, 15, 29, 35, 24797, 47495, 1928595, 8807085, 10504785, 24848081, 91381387, 274144161, ..., . LINKS Robert G. Wilson v, Table of n, a(n) for n = 1..55 EXAMPLE a(5) equals 29 because 15152527 (mod 27) == 19, but 15152529 (mod 29) == 0. MATHEMATICA 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] CROSSREFS Cf. A171785. Sequence in context: A066548 A075359 A190971 * A075336 A031236 A011535 Adjacent sequences: A228803 A228804 A228805 * A228807 A228808 A228809 KEYWORD nonn,base AUTHOR Robert G. Wilson v, Sep 04 2013 STATUS approved

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Last modified December 2 03:27 EST 2023. Contains 367505 sequences. (Running on oeis4.)