A064829 - OEIS

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A064829

Smallest number greater than 1 which ends in an odd digit in bases 2 through n.

3, 7, 7, 13, 13, 31, 31, 43, 43, 73, 73, 271, 271, 271, 271, 313, 313, 313, 313, 313, 313, 421, 421, 421, 421, 1303, 1303, 1303, 1303, 1303, 1303, 23563, 23563, 35803, 35803, 187003, 187003, 187003, 187003, 936703, 936703, 1426003, 1426003, 1426003, 1426003

(list; graph; refs; listen; history; text; internal format)

OFFSET

2,1

LINKS

Table of n, a(n) for n=2..46.

EXAMPLE

13 = 1101 in base 2, 231 in base 3, 31 in base 4, 23 in base 5, 21 in base 6 but 16 in base 7, so 13 ends in an odd digit from bases 2 to 6.

MAPLE

a:= proc(n) option remember; local k; for k by 2 from `if`(n=2, 3,

a(n-1)) while ormap(b-> irem(k, b)::even, [$2..n]) do od; k

end:

seq(a(n), n=2..52); # Alois P. Heinz, Jul 30 2023

MATHEMATICA

a[n_] := Module[{k = 3}, While[!AllTrue[Range[2, n], OddQ[Mod[k, #]] &], k += 2]; k]; Array[a, 45, 2] (* Amiram Eldar, Jul 30 2023 *)

CROSSREFS

Sequence in context: A073881 A137315 A139795 * A290649 A118259 A060845

Adjacent sequences: A064826 A064827 A064828 * A064830 A064831 A064832

KEYWORD

base,nonn

AUTHOR

Jonathan Ayres (jonathan.ayres(AT)btinternet.com), Oct 23 2001

EXTENSIONS

Data corrected by Sean A. Irvine, Jul 30 2023

STATUS

approved