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A305715 Irregular triangle whose rows are all finite sequences of positive integers that are polydivisible and strictly pandigital. 3
1, 1, 2, 1, 2, 3, 3, 2, 1, 1, 2, 3, 6, 5, 4, 3, 2, 1, 6, 5, 4, 3, 8, 1, 6, 5, 4, 7, 2, 3, 8, 1, 6, 5, 4, 7, 2, 9, 3, 8, 1, 6, 5, 4, 7, 2, 9, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
A positive integer sequence q of length k is strictly pandigital if it is a permutation of {1,2,...,k}. It is polydivisible if Sum_{i = 1...m} 10^(m - i) * q_i is a multiple of m for all 1 <= m <= k.
REFERENCES
Matt Parker, Things to make and do in the fourth dimension, 2015, pages 7-9.
LINKS
EXAMPLE
Triangle is:
{1}
{1,2}
{1,2,3}
{3,2,1}
{1,2,3,6,5,4}
{3,2,1,6,5,4}
{3,8,1,6,5,4,7,2}
{3,8,1,6,5,4,7,2,9}
{3,8,1,6,5,4,7,2,9,10}
MATHEMATICA
polyQ[q_]:=And@@Table[Divisible[FromDigits[Take[q, k]], k], {k, Length[q]}];
Flatten[Table[Select[Permutations[Range[n]], polyQ], {n, 8}]]
CROSSREFS
Sequence in context: A129570 A238385 A215652 * A165014 A358871 A357743
KEYWORD
base,fini,tabf,full,nonn
AUTHOR
Gus Wiseman, Jun 08 2018
STATUS
approved

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Last modified March 28 12:26 EDT 2024. Contains 371254 sequences. (Running on oeis4.)