OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
3 + 5 = 8, so 8 is in the sequence.
5 + 6 = 11, so 11 is in the sequence.
Although 12 can be expressed as a sum of two squarefree numbers, none of those sums (1 + 11, 2 + 10, 5 + 7, 6 + 6) involve successive squarefree numbers. Therefore 12 is not in the sequence.
MAPLE
N:= 1000; # to get entries up to approximately 2*N
SF:= select(numtheory:-issqrfree, [$1..N]):
seq(SF[i]+SF[i+1], i=1..nops(SF)-1); # Robert Israel, Jun 08 2014
MATHEMATICA
Abs[Differences[Select[Range[100], MoebiusMu[#] != 0 &] * (-1)^Range[61]]] (* Alonso del Arte, Jun 08 2014 *)
Total/@Partition[Select[Range[200], SquareFreeQ], 2, 1] (* Harvey P. Dale, Oct 09 2018 *)
PROG
(PARI) lista(nn) = {v = vector(nn, i, i); vsqf = select(n->issquarefree(n), v); for (i=1, #vsqf-1, print1(vsqf[i] + vsqf[i+1], ", "); ); } \\ Michel Marcus, May 31 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Juri-Stepan Gerasimov, May 30 2014
STATUS
approved