A038526 Concatenation of prime factors of n-th Fibonacci number.

2, 3, 5, 222, 13, 37, 217, 511, 89, 222233, 233, 1329, 2561, 3747, 1597, 2221719, 37113, 351141, 213421, 89199, 28657, 2222233723, 553001, 233521, 21753109, 31329281, 514229, 2225113161, 5572417, 37472207, 28919801, 15973571, 513141961, 22223331719107, 731492221

Offset

3,1

Links

Alois P. Heinz, Table of n, a(n) for n = 3..380

Formula

a(n) = A037276(A000045(n)). - R. J. Mathar, Oct 12 2007

Maple

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
# second Maple program:
F:= n-> (<<0|1>, <1|1>>^n)[1, 2]:
a:= n-> parse(cat(sort(map(i-> i[1]$i[2], ifactors(F(n))[2]))[])):
seq(a(n), n=3..40);  # Alois P. Heinz, Aug 17 2018

Crossrefs

Sequence in context: A041655 A082520 A062597 * A082755 A042067 A333803

Adjacent sequences: A038523 A038524 A038525 * A038527 A038528 A038529

Keyword

nonn,base

Author

Jeff Burch

Extensions

Edited by Charles R Greathouse IV, Apr 27 2010

Status

approved