Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #18 Aug 17 2018 13:09:34
%S 2,3,5,222,13,37,217,511,89,222233,233,1329,2561,3747,1597,2221719,
%T 37113,351141,213421,89199,28657,2222233723,553001,233521,21753109,
%U 31329281,514229,2225113161,5572417,37472207,28919801,15973571,513141961,22223331719107,731492221
%N Concatenation of prime factors of n-th Fibonacci number.
%H Alois P. Heinz, <a href="/A038526/b038526.txt">Table of n, a(n) for n = 3..380</a>
%F a(n) = A037276(A000045(n)). - _R. J. Mathar_, Oct 12 2007
%p A055642 := proc(n) if n =0 then 1 ; else ilog10(n)+1 ; fi ; end: catDigs := proc(L) local a,k,i ; a := 0 ; for i from 1 to nops(L) do a := a*10^A055642(L[i])+L[i] ; od ; end: A037276 := proc(n) local L,i,ifs,j ; if n = 1 then 0 else ifs := ifactors(n)[2] ; L := [] ; for i in ifs do for j from 1 to op(2,i) do L := [op(L),op(1,i)] ; od: od: catDigs(L) ; fi ; end: A038526 := proc(n) A037276(combinat[fibonacci](n)) ; end: seq(A038526(n),n=3..20) ; # _R. J. Mathar_, Oct 12 2007
%p # second Maple program:
%p F:= n-> (<<0|1>, <1|1>>^n)[1, 2]:
%p a:= n-> parse(cat(sort(map(i-> i[1]$i[2], ifactors(F(n))[2]))[])):
%p seq(a(n), n=3..40); # _Alois P. Heinz_, Aug 17 2018
%K nonn,base
%O 3,1
%A _Jeff Burch_
%E Edited by _Charles R Greathouse IV_, Apr 27 2010