|
|
A165420
|
|
a(1) = 1, a(2) = 2, a(n) = product of the previous terms for n >= 3.
|
|
5
|
|
|
1, 2, 2, 4, 16, 256, 65536, 4294967296, 18446744073709551616, 340282366920938463463374607431768211456, 115792089237316195423570985008687907853269984665640564039457584007913129639936
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
a(1) = 1, a(2) = 2, a(n) = Product_{i=1..n-1} a(i), n >= 3.
a(1) = 1, a(2) = 2, a(n) = A000079(2^(n-3)) = A001146(n-3) = 2^(2^(n-3)), n >= 3.
a(1) = 1, a(2) = 2, a(3) = 2, a(n) = (a(n-1))^2, n >= 4.
|
|
MATHEMATICA
|
a[1]:= 1; a[2]:= 2; a[n_]:= Product[a[j], {j, 1, n-1}]; Table[a[n], {n, 1, 12}] (* G. C. Greubel, Oct 19 2018 *)
|
|
PROG
|
(PARI) {a(n) = if(n==1, 1, if(n==2, 2, prod(j=1, n-1, a(j))))};
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|