OFFSET
1,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
Among the first 8 terms of the sequence there are 5 squarefree integers (1,2,6,15,19). So a(9) = a(8) + 5 = 24.
MAPLE
with(numtheory): a[1] := 1: for n from 2 to 60 do ct := 0: for j to n-1 do if abs(mobius(a[j])) > 0 then ct := ct+1 else ct := ct end if end do: a[n] := a[n-1]+ct end do: seq(a[n], n = 1 .. 60); # Emeric Deutsch, Jul 18 2007
MATHEMATICA
nxt[{t_, a_}]:={If[SquareFreeQ[t+a], 1, 0]+t, t+a}; Transpose[NestList[nxt, {1, 1}, 60]][[2]] (* Harvey P. Dale, Jan 04 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Jun 20 2007
EXTENSIONS
More terms from Emeric Deutsch and Joshua Zucker, Jul 18 2007
STATUS
approved