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A327451
a(1) = 1 and a(2) = 2; thereafter, if a(n) and a(n+1) do not share a digit, then a(n+2) = a(n) + a(n+1), otherwise a(n+2) is the smallest number not yet in the sequence.
1
1, 2, 3, 5, 8, 13, 21, 4, 25, 29, 6, 35, 41, 76, 117, 7, 9, 16, 25, 41, 66, 107, 173, 10, 11, 12, 14, 15, 17, 18, 19, 20, 39, 59, 22, 81, 103, 23, 24, 26, 27, 28, 30, 58, 88, 31, 119, 32, 151, 183, 33, 34, 36, 37, 38, 40, 78, 118, 42, 160, 202, 43, 245, 44, 45
OFFSET
1,2
COMMENTS
From Hans Havermann, Sep 22 2019: (Start)
Almost all adjacent terms share a digit. Looking only at terms that are sums (index,sum), from (3,3) to (107,239) there are 43 such. From here on to term 10^3 are 16 more; from 10^3 to 10^4, 16 more; and so on:
(125,198) (1013,1998) (10015,19998) (100017,199998)
(212,399) (2007,3999) (20009,39999) (200011,399999)
(213,599) (2008,5999) (20010,59999) (200012,599999)
(215,800) (2010,8000) (20012,80000) (200014,800000)
(310,599) (3009,5999) (30011,59999) (300013,599999)
(311,899) (3010,8999) (30012,89999) (300014,899999)
(313,1200) (3012,12000) (30014,120000) (300016,1200000)
(411,798) (4011,7998) (40013,79998) (400015,799998)
(412,1198) (4012,11998) (40014,119998) (400016,1199998)
(513,999) (5013,9999) (50015,99999) (500017,999999)
(514,1499) (5014,14999) (50016,149999) (500018,1499999)
(614,1198) (6014,11998) (60016,119998) (600018,1199998)
(615,1798) (6015,17998) (60017,179998) (600019,1799998)
(715,1399) (7016,13999) (70018,139999) (700020,1399999)
(716,2099) (7017,20999) (70019,209999) (700021,2099999)
(815,1600) (8017,16000) (80019,160000) (800021,1600000)
It appears that this pattern will continue forever. (End)
REFERENCES
Éric Angelini, Posting to Sequence Fans Mailing List, Sep 13 2019.
LINKS
CROSSREFS
Sequence in context: A345095 A281408 A359128 * A137290 A268962 A121104
KEYWORD
nonn,base
AUTHOR
N. J. A. Sloane, Sep 22 2019
EXTENSIONS
More terms from Lars Blomberg, Sep 22 2019
STATUS
approved