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A029454
Numbers k that divide the (right) concatenation of all numbers <= k written in base 9 (most significant digit on left).
1
1, 3, 9, 27, 33, 47, 51, 64, 81, 97, 135, 153, 192, 243, 405, 576, 729, 933, 1152, 2187, 3456, 6561, 9099, 10368, 19683, 27008, 31104, 59049, 72981, 91584, 108864, 111537, 126021, 137781, 139968, 177147, 260253, 326592, 413343, 419904, 438543, 531441, 553797, 626624
OFFSET
1,2
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..110
MATHEMATICA
b = 9; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[c, IntegerDigits[#, b]], b], #] &] (* Robert Price, Mar 11 2020 *)
PROG
(PARI) lista(nn, m=9) = my(t); for(k=1, nn, t=t*m^(1+logint(k, m))+k; if(t%k==0, print1(k, ", "))); \\ Jinyuan Wang, May 03 2025
(Python)
def ok(k): return concat_mod(9, k, k) == 0 # uses concat_mod by Jason Yuen in A029455
print([k for k in range(1, 10**5) if ok(k)]) # Michael S. Branicky, Apr 29 2026
KEYWORD
nonn,base
EXTENSIONS
More terms from David W. Wilson
a(42)-a(44) from Jinyuan Wang, May 03 2025
STATUS
approved