A075107 -id:A075107 - cp's OEIS frontend

A075108 First integer reached when starting with n/floor(log_2(n)) and iterating the map x -> x*ceiling(x) A075107(n) times, or -1 if no integer is ever reached.

2, 3, 2, 60, 3, 14, 8, 3, 1484710602474311520, 220, 4, 227370, 560, 5, 4, 218790, 268065, 570, 5, 1008, 33, 1458660, 6, 1925, 2093, 2268, 7, 58, 60, 62, 2016, 494764640798827359861461484, 5220768, 7

Offset: 2

Reinhard Zumkeller, Sep 02 2002

nonn

			n=5: after A075107(5)=2 steps 5/floor(log_2(5)) = 5/2 -> 15/2 -> 60, therefore a(5)=60.

Cf. A075103, A075121.

A075120 Number of steps to reach the first integer (= A075121(n)) starting with n/floor(sqrt(n)) and iterating the map x -> x*ceiling(x), or -1 if no integer is ever reached.

Original entry on oeis.org

0, 0, 0, 0, 2, 0, 1, 0, 0, 5, 2, 0, 3, 2, 0, 0, 3, 3, 2, 0, 2, 1, 3, 0, 0, 8, 3, 5, 2, 0, 3, 2, 5, 3, 0, 0, 6, 2, 2, 4, 2, 0, 5, 3, 1, 4, 2, 0, 0, 7, 12, 5, 11, 12, 2, 0, 4, 3, 9, 12, 6, 16, 0, 0, 3, 7, 8, 4, 4, 4, 2, 0, 2, 4, 5, 1, 5, 2, 5, 0, 0, 7, 3, 22, 3, 3

Offset: 1

Reinhard Zumkeller, Sep 03 2002

nonn

Starting with A073890(n)/A075119(n).

			a(13)=3 since 13/floor(sqrt(13)) = 13/3 -> 65/3 -> 1430/3 -> 227370 = A075121(13).

Cf. A068119, A073524, A075102, A075107, A075121.

More terms from Jinyuan Wang, Jan 15 2022

cp's OEIS Frontend

A075108 First integer reached when starting with n/floor(log_2(n)) and iterating the map x -> x*ceiling(x) A075107(n) times, or -1 if no integer is ever reached.

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