|
%I #16 Jun 25 2020 04:17:06
%S 3,6,1,2,1,4,5,6,59,2,1,4,5,6,1,6,3,2,3,10,7,2,7,4,3,4,1,14,1,2,5,10,
%T 1,2,1,2,3,6,7,2,1,14,21,10,11,6,3,4,5,6,1,12,9,34,3,22,11,2,1,2,15,
%U 18,1,12,3,2,9,6,1,12,1,2,5,4,5,8,13,8,5,4,7,2,3,2,9,4,5,2,1,8,3,4,1,6,1
%N a(n) is the smallest positive k such that k concatenated with k + n is a lucky number.
%C First terms of sequences A032640-A032649, continued with displacements n > 9.
%H Michael De Vlieger, <a href="/A032660/b032660.txt">Table of n, a(n) for n = 0..1000</a>
%e 77th term = 13: 13 + 76 (=77-1) = 89: '13' and '89' = 1389 equals a lucky number.
%t Block[{L = Array[2 # + 1 &, 10^5 + 1, 0], m, n, r, s}, For[n = 2, n < Length[L], r = L[[n++]]; L = ReplacePart[L, Table[r*i -> Nothing, {i, 1, Length[L]/r}]]]; m = Max[L]; Array[Block[{k = 1}, While[And[# < m, FreeQ[L, #]] &@ Set[s, FromDigits@ Join[IntegerDigits[k], IntegerDigits[k + #]]], k++]; If[s <= m, k, -1]] &, 95, 0]] (* _Michael De Vlieger_, Jun 24 2020, after _Jean-François Alcover_ at A000959 *)
%Y Cf. A000959, A032661.
%K nonn,base
%O 0,1
%A _Patrick De Geest_, May 15 1998
|
