cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A331475 a(n) is the smallest n-digit number using each digit 0 to n-1 once, such that the numbers formed by its last k digits are divisible by k, (k = 1..n).

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%I A331475 #38 May 04 2020 04:57:35
%S A331475 0,10,102,3012,13240,123540,3516240,16453720,123567480,9123567480
%N A331475 a(n) is the smallest n-digit number using each digit 0 to n-1 once, such that the numbers formed by its last k digits are divisible by k, (k = 1..n).
%C A331475 a(n) = A147636(n) for n=1, 2, 3, 9 and 10.
%e A331475 a(3) = 3012 because 2, 12, 012, 3012 are divisible by 1, 2, 3, 4 and it is the least such number with distinct digits 0 to 3.
%t A331475 ok[n_] := AllTrue[Range@ IntegerLength@ n, Mod[ Mod[n, 10^#], #] == 0 &]; a[n_] := SelectFirst[ FromDigits /@ Permutations[Range[0, n-1]], # >= 10^(n-1) - 1 && ok[#] &]; Array[a, 10] (* _Giovanni Resta_, May 04 2020 *)
%Y A331475 Cf. A147636, A158242, A220491.
%K A331475 base,fini,full,nonn
%O A331475 1,2
%A A331475 _Eduardo P. Feitosa_, May 03 2020