OFFSET
1,2
COMMENTS
This is a "doubly-recursed" version of A249817.
For primes p_n, a(p_n) = p_{a(n)}.
The first 7-cycle occurs at: (33 39 63 57 99 81 45), which is mirrored by the cycle (66 78 126 114 198 162 90) with terms double the size and also by the cycle (137 167 307 269 523 419 197), consisting of primes (p_33, p_39, p_63, ...).
LINKS
FORMULA
EXAMPLE
For n = 42 = 2*3*7, we see that it occurs as the 21st term on the top row of A246278 (A055396(42) = 1 and A246277(42) = 21), recursing on both yields a(1) = 1, a(21) = 27, thus we find A083221(1,27), the 27th term on A083221's topmost row (also A005843) which is 54, thus a(42) = 54.
Examples for cases where n is a prime:
a(3709) = a(p_518) = p_{a(518)} = A000040(1162) = 9397.
a(3719) = a(p_519) = p_{a(519)} = A000040(1839) = 15767.
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 17 2014
STATUS
approved