cp's OEIS Frontend

A115037 A number n is included if largest prime (or 1 if no prime divides) dividing the n-th Fibonacci number is itself a Fibonacci number.

%I A115037 #26 May 19 2020 19:12:34
%S A115037 1,2,3,4,5,6,7,11,12,13,17,23,29,43,46,47,58,69,83,86,129,131,137,141,
%T A115037 166,262,274,332,359,411,431,433,449,509,569,571,718,862,866,898,1018,
%U A115037 1138,1142,1293,1347,1436
%N A115037 A number n is included if largest prime (or 1 if no prime divides) dividing the n-th Fibonacci number is itself a Fibonacci number.
%C A115037 A001605 is a subsequence. 2036 and 2276 are also terms. - _Chai Wah Wu_, May 19 2020
%e A115037 The 12th Fibonacci number is 144. The largest prime dividing 144 is 3 and 3 is the 4th Fibonacci number. So 12 is in the sequence.
%o A115037 (PARI) isfib(n) = my(k=n^2); k+=(k+1)<<2; issquare(k) || (n>0 && issquare(k-8));
%o A115037 isok(n) = my(f=fibonacci(n)); (f==1) || isfib(vecmax(factor(f)[,1])); \\ _Michel Marcus_, Sep 06 2019
%Y A115037 Cf. A000045, A001605, A060385.
%K A115037 nonn,more
%O A115037 1,2
%A A115037 _Leroy Quet_, Feb 26 2006
%E A115037 More terms from _Diana L. Mecum_, Jun 02 2007
%E A115037 a(28)-a(40) from _Michel Marcus_, Sep 06 2019
%E A115037 a(41)-a(46) from _Chai Wah Wu_, May 19 2020