A167401 -id:A167401 - cp's OEIS frontend

A167856 Indices of records in A167401.

2, 4, 6, 10, 12, 18, 20, 24, 30, 42, 60, 84, 120, 140, 168, 180, 210, 330, 390, 420, 630, 660, 780, 840, 1260, 1680, 1848, 1980, 2310, 2730, 3570, 3990, 4290, 4620, 5460, 6930, 7140, 7980, 8190, 8580, 9240, 10920, 13860, 16380, 18480, 21420, 23940, 25740, 27720

Offset: 1

J. Lowell, Nov 13 2009

nonn

Cf. A167401.

a(12) from R. J. Mathar, Apr 28 2010
a(13)-a(41) from Rémy Sigrist, Jun 03 2019
a(42)-a(49) from Jinyuan Wang, Aug 21 2021

A213919 Triangle read by rows: T(n,m) = (n/k)^(k-1), where k is the m-th divisor of n, 1 <= m <= tau(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 4, 1, 1, 1, 1, 4, 8, 1, 1, 9, 1, 1, 5, 16, 1, 1, 1, 1, 6, 16, 27, 32, 1, 1, 1, 1, 7, 64, 1, 1, 25, 81, 1, 1, 8, 64, 128, 1, 1, 1, 1, 9, 36, 243, 256, 1, 1, 1, 1, 10, 125, 256, 512, 1, 1, 49, 729, 1, 1, 11, 1024, 1, 1, 1, 1, 12, 64, 216, 1024, 2187, 2048, 1, 1, 625, 1, 1, 13, 4096, 1, 1, 81, 6561, 1, 1, 14, 343, 4096

Offset: 1

Gerasimov Sergey, Mar 05 2013

Divisor k of composite number n with maximal value (n/k)^(k-1): 2, 3, 4, 3, 5, 6, 7, 5, 8, 9, 10, 7, 11, 8, 5, 13, 9, 14,...

			Triangle begins:
  1;
  1, 1;
  1, 1;
  1, 2, 1;
  1, 1;
  1, 3, 4, 1;
  1, 1;
  1, 4, 8, 1;
  1, 9, 1;
  1, 5, 16, 1;
  1, 1;
  1, 6, 16, 27, 32, 1.

Cf. A000005 (row lengths), A027750, A087909 (row sums), A167401, A208239.

T(n,k) = A027750(n, A000005(n) + 1 - k)/(A027750(n,k) - 1), 1 <= k <= A000005(n).

a(83) corrected by Jason Yuen, Oct 27 2024

cp's OEIS Frontend

A167856 Indices of records in A167401.

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A213919 Triangle read by rows: T(n,m) = (n/k)^(k-1), where k is the m-th divisor of n, 1 <= m <= tau(n).

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