|
|
A092124
|
|
a(0) = 2, a(n) = (2^(2^n)+2)*a(n-1) for n>0.
|
|
4
|
|
|
2, 12, 216, 55728, 3652301664, 15686516209310983872, 289365149921256212111714425927549504896, 98465858119637274097902770931519409290135390781788892125023848289699334298368
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
COMMENTS
|
In binary representation a(n) can be interpreted as an expression to represent n according to John von Neumann's definition of natural numbers: braces are coded as 1 and 0 and the empty set as 10={};
|
|
LINKS
|
|
|
EXAMPLE
|
a(3)=55728='1101100110110000' -> {{}{{}}{{}{{}}}} -> {{},{{}},{{},{{}}}} -> {0,{0},{0,{0}}} -> {0,1,{0,1}} -> {0,1,2} -> A001477(3)=3.
|
|
MATHEMATICA
|
RecurrenceTable[{a[0]==2, a[n]==(2^(2^n)+2)a[n-1]}, a, {n, 8}] (* Harvey P. Dale, Nov 15 2020 *)
nxt[{n_, a_}]:={n+1, (2^2^(n+1)+2)a}; NestList[nxt, {0, 2}, 8][[;; , 2]] (* Harvey P. Dale, Aug 11 2023 *)
|
|
PROG
|
(Python)
from functools import lru_cache
@lru_cache(maxsize=None)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|