login
A328316
Iterates of A276086 starting from 0.
15
0, 1, 2, 3, 6, 5, 18, 125, 43218, 258413198822535882125
OFFSET
0,3
COMMENTS
The unique infinite sequence such that a(0) = 0, a(n) = A276085(a(n+1)) for n >= 0, and A129251(a(n)) = 0 for n >= 1, i.e., all nonzero terms must be in A048103.
a(10) is 240 decimal digits long (can be found in b-file), and a(11) is too big to fit even into a b-file as it is 32700 decimal digits long, but it can be found in the given a-file.
FORMULA
a(0) = 0; and for n > 0, a(n) = A276086(a(n-1)).
MATHEMATICA
A276086[n0_] := Module[{m = 1, i = 1, n = n0, p}, While[n > 0, p = Prime[i]; m *= p^Mod[n, p]; n = Quotient[n, p]; i++]; m];
NestList[A276086, 0, 10] (* Jean-François Alcover, Dec 01 2021, after Antti Karttunen in A276086 *)
PROG
(PARI)
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A328316(n) = if(!n, 0, A276086(A328316(n-1)));
CROSSREFS
Cf. A153013, and also A179016, A219666, A259934 for more or less analogous sequences.
Cf. also A328313.
Sequence in context: A332461 A319344 A260443 * A373003 A206242 A327454
KEYWORD
nonn
AUTHOR
Antti Karttunen, Oct 14 2019
STATUS
approved