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A029520
Numbers k such that k divides the (left) concatenation of all numbers <= k written in base 3 (most significant digit on right and removing all least significant zeros before concatenation).
1
1, 4, 5, 7, 19, 443, 19952, 81544, 919648, 1186844
OFFSET
1,2
COMMENTS
This sequence differs from A061956 in that all least significant zeros are removed before concatenation.
No more terms < 10^7. [Lars Blomberg, Sep 02 2011]
EXAMPLE
See A029519 for example.
MATHEMATICA
b = 3; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[IntegerDigits[IntegerReverse[#, b], b], c], b], #] &] (* Robert Price, Mar 13 2020 *)
PROG
(J) ab=. #.^:_1
mkcat=. [ ab&.> [ #.&.> [ |.@:ab&.> [: |. [: >: [: i. ]
seq=. ] +. [ #. [: ; mkcat
3 (] #~ ] = seq"0) >: i.500x NB. Stephen Makdisi, May 03 2018
KEYWORD
nonn,base,more,changed
EXTENSIONS
Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002
Additional comments and more terms from Larry Reeves (larryr(AT)acm.org), Jun 04 2001
a(9)-a(10) from Lars Blomberg, Sep 02 2011
STATUS
approved