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A080430 a(n) = least odd number such that all pairwise sums a(i) + a(j), i < j <= n, are distinct. 3
1, 3, 5, 9, 15, 25, 41, 59, 77, 105, 147, 189, 255, 303, 363, 423, 515, 631, 747, 825, 951, 1061, 1091, 1215, 1433, 1595, 1723, 1929, 2119, 2321, 2613, 2771, 2869, 3111, 3443, 3667, 3867, 4115, 4521, 4993, 5397, 5747, 6121, 6393, 6663, 7257, 7423, 7735, 8279 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Zak Seidov, Table of n, a(n) for n = 1..127

MAPLE

S := {4}: A := array(1..10^4): for m from 1 to 10^4 do A[m] := 0 od: A[1] := 1: A[3] := 3: for n from 5 to 10^4-1 by 2 do mytest := 0: for j from 1 to n-2 by 2 do if A[j]>0 then if member(A[j]+n, S) then mytest := 1; break; fi:fi:od: if mytest=0 then A[n] := n; for j from 1 to n-2 by 2 do S := S union {A[j]+n} od: fi: od: for i from 1 to 10^4-1 by 2 do if A[i]>0 then printf(`%d, `, A[i]) fi: od: # James A. Sellers, Feb 26 2003

MATHEMATICA

s = {1, 3}; s2 = {4}; k = 5; Do[Label[kk]; If[Intersection[s + k, s2] == {}, s2 = Flatten[{s + k, s2}]; AppendTo[s, k]]; k = k + 2; If[k < 10000, Goto[kk]], {1}]; s (* Zak Seidov, Dec 23 2014 *)

CROSSREFS

Cf. A080429.

Sequence in context: A029877 A207641 A147425 * A053523 A053522 A053521

Adjacent sequences:  A080427 A080428 A080429 * A080431 A080432 A080433

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Feb 20 2003

EXTENSIONS

More terms from James A. Sellers, Feb 26 2003

STATUS

approved

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Last modified February 22 01:04 EST 2019. Contains 320381 sequences. (Running on oeis4.)