A029913 - OEIS

A029913

Start with n; if prime, stop; repeatedly sum squares of prime factors (counted with multiplicity), until reach 16 or a prime; set a(n) = 0 if no limit exists.

%I #13 Mar 08 2020 23:53:40

%S 2,3,17,5,13,7,17,59,29,11,17,13,53,293,16,17,59,19

%N Start with n; if prime, stop; repeatedly sum squares of prime factors (counted with multiplicity), until reach 16 or a prime; set a(n) = 0 if no limit exists.

%e 9 -> 3^2 + 3^2 = 18 -> 4 + 9 + 9 = 22 -> 4 + 121 = 125 -> 25 + 25 + 25 = 75 -> 9 + 25 + 25 = 59, so a(9) = 59.

%Y Cf. A029914.

%K nonn,more

%O 2,1

%A _Dann Toliver_

%E More terms from _Michel ten Voorde_, Apr 12 2001

%E Incorrect extension reverted by _Sean A. Irvine_, Mar 08 2020