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A225523 Number of distinct products i*j over all pairs (i,j) with |i| + |j| <= n. 2
1, 1, 3, 5, 9, 11, 17, 21, 27, 33, 39, 43, 53, 59, 69, 79, 89, 97, 107, 117, 131, 143, 157, 167, 183, 195, 209, 223, 237, 249, 269, 283, 301, 317, 335, 353, 373, 389, 409, 427, 449, 465, 491, 509, 535, 557, 581, 603, 631, 657, 679 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

This sequence is in reply to an extension request made in A100449.

LINKS

Robert Price, Table of n, a(n) for n = 0..400

MATHEMATICA

f[n_]:=Length[Complement[Union[Flatten[Table[If[Abs[i]+Abs[j]<=n, {i*j}], {i, -n, n}, {j, -n, n}], 1]], {Null}]]; Table[f[n], {n, 0, 100}]

CROSSREFS

Cf. A018805, A027430, A100448, A100449, A100450, A213207.

Sequence in context: A117992 A015614 A138203 * A007952 A145819 A317827

Adjacent sequences:  A225520 A225521 A225522 * A225524 A225525 A225526

KEYWORD

nonn,easy

AUTHOR

Robert Price, May 09 2013

STATUS

approved

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Last modified April 14 03:53 EDT 2021. Contains 342941 sequences. (Running on oeis4.)