OFFSET
1,2
LINKS
Carole Dubois, Table of n, a(n) for n = 1..5001
EXAMPLE
1, 10, 11, 91, 12, 19, 79, 78, 8,
a(1) = 1, a(2) = 10 and 11 (sum 1 + 10) have at least the digit 1 in common;
a(2) = 10, a(3) = 11 and 21 (sum 10 + 11) have at least the digit 1 in common;
a(3) = 11, a(4) = 91 and 102 (sum 11 + 91) have at least the digit 1 in common;
a(4) = 91, a(5) = 12 and 103 (sum 91 + 12) have at least the digit 1 in common;
a(5) = 12, a(6) = 19 and 31 (sum 12 + 19) have at least the digit 1 in common;
a(6) = 19, a(7) = 79 and 98 (sum 19 + 79) have at least the digit 9 in common;
a(7) = 79, a(8) = 78 and 157 (sum 79 + 78) have at least the digit 7 in common; etc.
MATHEMATICA
Nest[Append[#1, Block[{k = 2}, While[Nand[FreeQ[#1, k], Length@ Intersection[#2, IntegerDigits[k], IntegerDigits[k + #1[[-1]] ]] > 0], k++]; k]] & @@ {#, IntegerDigits[#[[-1]] ]} &, {1}, 75] (* Michael De Vlieger, Jan 21 2020 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Eric Angelini and Carole Dubois, Jan 21 2020
STATUS
approved