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A225530 Number of ordered pairs (i,j) with i,j >= 0, i + j = n and gcd(i,j) <= 1. 3
1, 2, 1, 2, 2, 4, 2, 6, 4, 6, 4, 10, 4, 12, 6, 8, 8, 16, 6, 18, 8, 12, 10, 22, 8, 20, 12, 18, 12, 28, 8, 30, 16, 20, 16, 24, 12, 36, 18, 24, 16, 40, 12, 42, 20, 24, 22, 46, 16, 42, 20, 32, 24, 52, 18, 40, 24, 36, 28, 58, 16, 60, 30, 36, 32, 48, 20, 66 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
This sequence is in reply to an extension request made in A100449.
Note that gcd(0,m) = m for any m.
Apparently a(n) = A000010(n), n >= 2. - R. J. Mathar, May 11 2013
LINKS
MATHEMATICA
f[n_]:=Length[Complement[Union[Flatten[Table[If[i+j==n&&GCD[i, j]<=1, {i, j}], {i, 0, n}, {j, 0, n}], 1]], {Null}]]; Table[f[n], {n, 0, 100}]
CROSSREFS
Sequence in context: A102722 A339219 A308302 * A020475 A156995 A131183
KEYWORD
nonn,easy
AUTHOR
Robert Price, May 09 2013
STATUS
approved

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Last modified March 29 04:59 EDT 2024. Contains 371264 sequences. (Running on oeis4.)