The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A367897 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A367897

a(1)=1, a(n) = H_(n-2)(a(n-2), a(n-1)) where H_n is the n-th hyperoperator.
(history; published version)

#21 by Peter Luschny at Sun Jan 21 09:16:49 EST 2024

STATUS

reviewed

approved

#20 by Stefano Spezia at Sun Jan 21 02:08:25 EST 2024

STATUS

proposed

reviewed

#19 by Joerg Arndt at Sun Jan 21 01:43:45 EST 2024

STATUS

editing

proposed

#18 by Joerg Arndt at Sun Jan 21 01:43:32 EST 2024

EXAMPLE

a(1)=1, a(2)=S(a(1)), a(3)=a(1)+a(2), a(4)=a(2)*a(3), a(5)=a(3)^a(4), a(6)=a(4)^^a(5), ...a(1) = 1

a(2) = H_0(a(1), a(1)) = 1 + 1 = 2 (successor of 1 = 2)

a(3) = H_1(a(1), a(2)) = 1 + 2 = 3

a(4) = H_2(a(2), a(3)) = 2 * 3 = 6

a(5) = H_3(a(3), a(4)) = 3^6 = 729

STATUS

proposed

editing

#17 by Peter Woodward at Sun Jan 21 00:22:41 EST 2024

STATUS

editing

proposed

#16 by Peter Woodward at Sun Jan 21 00:18:06 EST 2024

NAME

a(1)=1, a(n) = H_(n-2)(a(n-12), a(n-21)) where H_n is the n-th hyperoperator.

STATUS

approved

editing

Discussion

Sun Jan 21

00:22

Peter Woodward: Switched (n-1) and (n-2) in the title.
a(1) = 1 (given)
a(2) = H_0(a(1), a(1)) = 1 + 1 = 2 (successor of 1 = 2)
a(3) = H_1(a(1), a(2)) = 1 + 2 = 3
a(4) = H_2(a(2), a(3)) = 2 * 3 = 6
a(5) = H_3(a(3), a(4)) = 3^6 = 729

#15 by N. J. A. Sloane at Sat Jan 20 03:56:42 EST 2024

STATUS

proposed

approved

#14 by Peter Woodward at Tue Dec 26 14:29:27 EST 2023

STATUS

editing

proposed

Discussion

Tue Dec 26

14:58

Michel Marcus: yes

#13 by Peter Woodward at Tue Dec 26 14:19:31 EST 2023

LINKS

Wikipedia, <a href="https://en.wikipedia.org/wiki/Generalizations_of_Fibonacci_numbers">Generalizations of Fibonacci numbers</a>

STATUS

proposed

editing

Discussion

Tue Dec 26

14:29

Peter Woodward: @Michel Marcus: I fixed wiki link, sorry. Yes A189896 has 4 terms: successor, addition, multiplication, exponentiation, and for the 5th states: The term is too big to be included (4^^4). 

I meant "arbitrary to stop at a(5)" in the conceptual sense, I understand 6^^729 is an actual stumbling block for written depiction, which we cannot even estimate as far as I know.

#12 by Peter Woodward at Tue Dec 26 11:40:37 EST 2023

STATUS

editing

proposed

Discussion

Tue Dec 26

12:00

Michel Marcus: the new link is not ok

12:03

Michel Marcus: yes  A189896  .... 4 terms ....

12:08

Michel Marcus: arbitrary to stop at a(5) ??   how big would it be ???