A075120 -id:A075120 - cp's OEIS frontend

A075121 First integer reached when starting with n/floor(sqrt(n)) and iterating the map x -> x*ceiling(x) A075120(n) times, or -1 if no integer is ever reached.

1, 2, 3, 2, 60, 3, 14, 4, 3, 1484710602474311520, 220, 4, 227370, 560, 5, 4, 218790, 268065, 570, 5, 1008, 33, 1458660, 6, 5

Offset: 1

Reinhard Zumkeller, Sep 03 2002

nonn

a(26) = 9.20120538...*10^191 is too large to be included in Data. - Jinyuan Wang, Jan 15 2022

			n=13: after A075120(13)=3 steps 13/floor(sqrt(13)) = 13/3 -> 65/3 -> 1430/3 -> 227370, therefore a(13)=227370.

Jinyuan Wang, Table of n, a(n) for n = 1..50

Cf. A075103, A075108, A075120.

A075107 Number of steps to reach the first integer (= A075108(n)) starting with n/floor(log_2(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, 2, 0, 1, 1, 0, 5, 2, 0, 3, 2, 0, 0, 3, 3, 2, 0, 2, 1, 3, 0, 2, 2, 2, 0, 1, 1, 1, 2, 5, 3, 0, 16, 2, 4, 6, 0, 4, 16, 9, 2, 0, 1, 1, 1, 1, 0, 4, 2, 4, 8, 0, 2, 5, 2, 8, 0, 9, 3, 4, 5, 2, 0, 1, 1, 1, 1, 1, 0, 5, 7, 3, 2, 4, 0, 9, 4, 1, 2, 3, 0, 4, 1, 2, 1

Offset: 2

Reinhard Zumkeller, Sep 02 2002

nonn

Starting values given by A075105(n)/A075106(n).

			a(5)=2 since 5/floor(log_2(5)) = 5/2 -> 15/2 -> 60 = A075108(5).

Cf. A068119, A073524, A075102, A075120.

More terms from Jinyuan Wang, Jan 15 2022

cp's OEIS Frontend

A075121 First integer reached when starting with n/floor(sqrt(n)) and iterating the map x -> x*ceiling(x) A075120(n) times, or -1 if no integer is ever reached.

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