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A362779 Triangular array read by rows: T(n,k) is the greatest prime factor of n!*k + 1, n >= 1, 1 <= k <= n. 2

%I #12 Jun 25 2023 01:03:19

%S 2,3,5,7,13,19,5,7,73,97,11,241,19,37,601,103,131,2161,67,277,149,71,

%T 593,15121,20161,79,30241,35281,661,7331,1657,161281,449,241921,

%U 282241,6863,269,2477,1088641,1451521,78887,2177281,5281,2903041,192113,329891,29383,10886401,62297,18144001,2243,251501,29030401,32659201,843907

%N Triangular array read by rows: T(n,k) is the greatest prime factor of n!*k + 1, n >= 1, 1 <= k <= n.

%C The primes in each row are distinct because n!*k + 1 are coprime for 1 <= k <= n, and hence this array gives a simple proof that there are infinitely many prime numbers.

%F T(n,k) = A006530(A362777(n,k))

%e Triangle T(n,k) begins:

%e n\k 1 2 3 4 5 6 ...

%e 1 2

%e 2 3 5

%e 3 7 13 19

%e 4 5 7 73 97

%e 5 11 241 19 37 601

%e 6 103 131 2161 67 277 149

%e ...

%Y Cf. A362777, A362778.

%Y Cf. A002583 (1st column).

%K tabl,nonn

%O 1,1

%A _Joe B. Stephen_, May 03 2023

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Last modified September 9 22:43 EDT 2024. Contains 375765 sequences. (Running on oeis4.)