OFFSET
1,1
COMMENTS
Record values: 3, 6, 9, 22, 30, 40, 44, 45, 51, 52, 53, 61, 62, 63, 64, 71, 72, 90, 91, 100, 111, 112, 222, 223, 224, 225, 226, 300, 400, 404, 500, 505, 506, 507, 600, 601, 602, 700, 701, 702, 703, 800, 811, 900, 901, 902, 1000, 1111, 1112, 1113, 1114, 1117, 1121, 2222, 3000, 3003, 3004, 3005, 3333, 3334, 4444, 4445, 4446, 4447, 5000, 5005, 5555, 6000, 6006, 6007, 6008, 6009, 6060, 6066, 6067, 6068, 6069, 6070, 6076, 6111, 7000, 7002, 7007, 7008, 7009, 7010, 7011, 8000, 8001, 8002, 8008, 8010, 8011, 8012, 8111, 9000, 9001, 9002, 10000, 11111, 11112, 11113, 11114, 11115, 20000, 20002, 20003, 20004, 22222, 33333, 33334, 33335, 40000, 40004, 40005, 40006, 40007, 40040, ..., . - Robert G. Wilson v, Sep 25 2010
Sequence has 12345677 terms, ending with a(12345677) = 9900000900009. - Michael S. Branicky, Apr 08 2023
LINKS
Robert G. Wilson v, Table of n, a(n) for n = 1..10000.
Michael S. Branicky, Python program
MATHEMATICA
f[s_List] := Block[{k = 1, len = Length@ s}, id = Union@ Flatten[ IntegerDigits /@ {len + 1, len + 2}]; While[ MemberQ[s, k] || Intersection[ id, IntegerDigits@ k] != {}, k++ ]; Append[s, k]]; Nest[f, {}, 72] (* Robert G. Wilson v, Sep 25 2010 *)
PROG
(Python) # see linked program generating full sequence
CROSSREFS
KEYWORD
nonn,base,fini
AUTHOR
N. J. A. Sloane, Sep 06 2010, based on an email from Eric Angelini, Jun 30 2010
EXTENSIONS
a(25) onwards from Robert G. Wilson v, Sep 25 2010
STATUS
approved