OFFSET
1,1
COMMENTS
L(m) = Lucas(m) = Fibonacci(m-1) + Fibonacci(m+1). 7 = L(4) divides L(4*(1+2m)) since L(4m) = L(4)*L(4*(m-1)) - L(4*(m-2)).
Integer k is in this sequence iff k is prime and 4k belongs to A085726. - Max Alekseyev, May 16 2010
a(14) > 60000. - Michael S. Branicky, Aug 01 2024
MATHEMATICA
a=7; b=47; Do[ c=7b-a; a=b; b=c; If[ PrimeQ[c/7], Print[n] ], {n, 3, 100}]
CROSSREFS
KEYWORD
less,more,nonn
AUTHOR
Alexander Adamchuk, May 14 2007, May 16 2007
EXTENSIONS
a(7) - a(10) from Stefan Steinerberger, May 17 2007
a(11) from Max Alekseyev, Nov 25 2007
a(12) from Alexander Adamchuk, May 15 2010
a(13) from Michael S. Branicky, Aug 01 2024
STATUS
approved