OFFSET
1,1
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).
PROG
(PARI) a(n) = if (n==1, 3, my(prec=a(n-1)); if (gcd(prec, n) > 1, prec/gcd(prec, n), n+prec)); \\ Michel Marcus, Jul 13 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Todor Szimeonov, Jul 13 2020
STATUS
approved