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A061974 Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 21 (most significant digit on right). 1
1, 5, 25, 125, 155, 160, 421, 1409, 729175, 2804576 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
This sequence differs from A029538 in that all least significant zeros are kept during concatenation.
No more terms < 7*10^6. - Lars Blomberg, Jul 27 2011
LINKS
EXAMPLE
See A061955 for example.
MATHEMATICA
b = 21; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[Reverse[IntegerDigits[#, b]], c], b], #] &] (* Robert Price, Mar 09 2020 *)
PROG
(PARI) lista(nn, m=21) = my(c, t); for(k=1, nn, t+=m^c*fromdigits(Vecrev(digits(k, m)), m); c+=logint(m*k, m); if(t%k==0, print1(k, ", "))); \\ Jinyuan Wang, Dec 05 2020
CROSSREFS
Sequence in context: A036151 A271380 A036149 * A015950 A337950 A366323
KEYWORD
nonn,base,more
AUTHOR
Larry Reeves (larryr(AT)acm.org), May 24 2001
EXTENSIONS
Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002
a(9)-a(10) from Lars Blomberg, Jul 27 2011
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)