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A171073
Smallest positive integer a(n) not yet in the sequence and sharing no digit with n, (n-1) or (n+1) in its decimal representation.
1
3, 4, 1, 2, 7, 8, 5, 6, 22, 23, 9, 40, 50, 20, 27, 24, 25, 26, 33, 34, 35, 44, 10, 11, 13, 14, 15, 16, 17, 45, 46, 47, 18, 12, 19, 21, 29, 41, 51, 28, 36, 55, 56, 60, 30, 31, 32, 52, 37, 38, 39, 48, 61, 62, 70, 42, 43, 63, 71, 72, 49, 54, 57, 77, 73, 80, 53, 100, 111, 58, 59, 64, 65
OFFSET
1,1
COMMENTS
Sequence has 1234567 terms, ending with a(1234567) = 9990990999. - Michael S. Branicky, Apr 08 2023
LINKS
Michael S. Branicky, Python program
MATHEMATICA
f[s_List] := Block[{k = 1, len = Length@s}, id = Union@ Flatten[ IntegerDigits /@ {len, len + 1, len + 2}]; While[ MemberQ[s, k] || Intersection[id, IntegerDigits@k] != {}, k++ ]; Append[s, k]]; Nest[f, {}, 73] (* Robert G. Wilson v, Sep 25 2010 *)
PROG
(Python) # see linked program generating full sequence
CROSSREFS
Cf. A171072. - Robert G. Wilson v, Sep 25 2010
Sequence in context: A021971 A260822 A256008 * A021297 A124909 A348354
KEYWORD
nonn,base,fini
AUTHOR
N. J. A. Sloane, Sep 06 2010, based on an email from Eric Angelini, Jun 30 2010
EXTENSIONS
a(22) inserted, a(25) and a(26) corrected, etc. by Robert G. Wilson v, Sep 25 2010
a(42) corrected by Michael S. Branicky, Apr 08 2023
STATUS
approved