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A079784 Triangle read by rows in which the n-th row contains the smallest set of n consecutive numbers such that the r-th number in the n-th row is divisible by n-r+1. The first term of the n-th row must exceed n. 3

%I #17 Mar 28 2024 14:13:32

%S 2,4,5,9,10,11,8,9,10,11,55,56,57,58,59,54,55,56,57,58,59,413,414,415,

%T 416,417,418,419,832,833,834,835,836,837,838,839,2511,2512,2513,2514,

%U 2515,2516,2517,2518,2519,2510,2511,2512,2513,2514,2515,2516,2517,2518,2519

%N Triangle read by rows in which the n-th row contains the smallest set of n consecutive numbers such that the r-th number in the n-th row is divisible by n-r+1. The first term of the n-th row must exceed n.

%e Triangle starts:

%e 2;

%e 4, 5;

%e 9, 10, 11;

%e 8, 9, 10, 11;

%e 55, 56, 57, 58, 59;

%e 54, 55, 56, 57, 58, 59;

%e 413, 414, 415, 416, 417, 418, 419;

%e ...

%e The fifth row 55,56,57,58,59 is divisible by 5,4,3,2 and 1 respectively.

%t T[n_, k_] := T[n, k] = Which[n == k == 1, 2, n == k == 2, 5, n == k == 3, 11, n == k, LCM @@ Range[n] - 1, True, T[n, k + 1] - 1];

%t Table[T[n, k], {n, 1, 10}, {k, 1, n}] // Flatten (* _Jean-François Alcover_, Mar 28 2024, after comments in A079782 *)

%Y Cf. A079781, A079782, A079783.

%K nonn,tabl

%O 1,1

%A _Amarnath Murthy_, Feb 03 2003

%E Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 29 2003

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Last modified May 7 06:05 EDT 2024. Contains 372300 sequences. (Running on oeis4.)