A361328 -id:A361328 - cp's OEIS frontend

A361327 a(n) is the greatest prime factor of A361321(n) with a(1) = 1.

1, 3, 5, 7, 7, 11, 11, 7, 13, 13, 5, 11, 11, 7, 13, 13, 17, 17, 19, 19, 17, 17, 7, 5, 23, 23, 19, 19, 11, 23, 23, 13, 11, 29, 29, 7, 13, 31, 31, 23, 23, 37, 37, 11, 29, 29, 11, 41, 41, 31, 31, 13, 43, 43, 37, 37, 17, 47, 47, 53, 53, 59, 59, 61, 61, 13, 13, 67, 67, 71, 71, 73, 73, 79, 79, 11, 17

Offset: 1

Scott R. Shannon, Rémy Sigrist and N. J. A. Sloane, Mar 15 2023

nonn

			A361321(3) = 10 = 2*5, so a(3) = 5.

Scott R. Shannon, Table of n, a(n) for n = 1..10000

Cf. A361321, A000469, A361328 (least prime factor), A361329, A361329, A336957, A360519, A361120.

A361329 a(n) = gcd(A361321(n), A361321(n+1)).

Original entry on oeis.org

1, 2, 5, 7, 3, 11, 2, 7, 13, 3, 5, 11, 7, 2, 13, 5, 17, 2, 19, 3, 17, 7, 10, 3, 23, 7, 19, 5, 2, 23, 13, 11, 2, 29, 5, 3, 2, 31, 5, 23, 2, 37, 5, 3, 29, 7, 2, 41, 3, 31, 7, 2, 43, 3, 37, 7, 2, 47, 3, 53, 2, 59, 3, 61, 2, 65, 3, 67, 2, 71, 3, 73, 2, 79, 3, 11, 17, 2, 19, 11, 23, 2, 17, 13, 19, 2

Offset: 1

Scott R. Shannon, Rémy Sigrist and N. J. A. Sloane, Mar 15 2023

nonn

			A361321(3) = 10, A361321(4) = 35, so a(3) = gcd(10,35) = 5;

Scott R. Shannon, Table of n, a(n) for n = 1..10000

Cf. A361321, A000469, A361327, A361328, A361329, A336957, A360519, A361118.

cp's OEIS Frontend

A361327 a(n) is the greatest prime factor of A361321(n) with a(1) = 1.

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