%I #19 Aug 29 2024 13:55:49
%S 0,0,0,1,0,2,3,2,0,5,0,4,3,4,0,5,4,2,7,4,0,17,8,14,31,14,0,37,20,26,9,
%T 20,22,11,6,12,15,32,18,17,0,16,43,24,0,17,20,26,27,20,6,9,12,34,29,
%U 36,30,47,48,4,45,32,54,27,132,22,31,4,32,11,12,60,7,76
%N a(n) is the difference between F=A000045(n) and the largest prime not exceeding F.
%H Amiram Eldar, <a href="/A375751/b375751.txt">Table of n, a(n) for n = 3..10000</a>
%F a(n) = A000045(n) - A138184(n).
%F a(n) = 0 <=> n in { A001605 }. - _Alois P. Heinz_, Aug 27 2024
%p a:= n-> (F-> F-prevprime(F+1))(combinat[fibonacci](n)):
%p seq(a(n), n=3..76); # _Alois P. Heinz_, Aug 27 2024
%t a[n_]:=Module[{p=2},While[(f=Fibonacci[n])>=p, pold=p;p=NextPrime[p]]; d=f-pold;If[d>0,f-pold,d=0]; d]; Array[a,74,3] (* _Stefano Spezia_, Aug 27 2024 *)
%t Map[(# - NextPrime[# + 1, -1]) &, Fibonacci[Range[3, 76]]] (* _Amiram Eldar_, Aug 29 2024 *)
%o (PARI) a(n) = my(F=fibonacci(n)); F-precprime(F)
%o (Python)
%o from sympy import prevprime, fibonacci
%o def A375753(n): return (F:=fibonacci(n)) - prevprime(F+1) # _Karl-Heinz Hofmann_, Aug 27 2024
%Y Cf. A000045, A007917, A001605, A138184, A138185, A159977, A159978, A202090.
%K nonn,easy
%O 3,6
%A _Hugo Pfoertner_, Aug 27 2024