OFFSET
1,4
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
EXAMPLE
For n=4, starting from k = ((4+1)^2)-1, and iterating k -> A255131(k), yields 24 -> 21 -> 18 -> 16 -> 15 -> 11 -> 8 -> 6 -> 3 before 0 is reached. Subtracting one from each gives [25, 22, 19, 17, 16, 12, 9, 7, 4], of which only 19, 17, and 7 are primes, thus a(4) = 3.
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 13 2016
STATUS
approved