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 A260998 Maximal size of a subset of Z_n with distinct sums of pairs (of distinct elements). 4
 1, 2, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Fausto A. C. Cariboni, Table of n, a(n) for n = 1..254 Fausto A. C. Cariboni, S_2-sets that yield a(n) for n = 2..254, Mar 24 2018. H. Haanpaa, A. Huima and P. R. J. Ostergard, Sets in Z_n with Distinct Sums of Pairs, in Optimal discrete structures and algorithms (ODSA 2000). Discrete Appl. Math. 138 (2004), no. 1-2, 99-106. [Annotated scanned copies of four pages only from preprint of paper] H. Haanpaa, A. Huima and P. R. J. Ostergard, Sets in Z_n with Distinct Sums of Pairs, in Optimal discrete structures and algorithms (ODSA 2000). Discrete Appl. Math. 138 (2004), no. 1-2, 99-106. FORMULA By the pigeonhole principle, C(a(n),2) <= n, yielding upper bound a(n) <= floor((1+sqrt(8*n+1))/2). - Rob Pratt, Nov 27 2017 CROSSREFS Cf. A004135, A004136, A260999. Sequence in context: A262070 A117806 A085423 * A324728 A327008 A316846 Adjacent sequences:  A260995 A260996 A260997 * A260999 A261000 A261001 KEYWORD nonn AUTHOR N. J. A. Sloane, Aug 10 2015 EXTENSIONS a(1)-a(90) from H. Haanpaa, A. Huima and P. R. J. Ostergard (see link), Nov 08 2000 a(1)-a(90) confirmed by Fausto A. C. Cariboni, Nov 09 2017 STATUS approved

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Last modified January 20 14:24 EST 2020. Contains 331094 sequences. (Running on oeis4.)