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 A122793 Connell sum sequence (partial sums of the Connell sequence). 7
 1, 3, 7, 12, 19, 28, 38, 50, 64, 80, 97, 116, 137, 160, 185, 211, 239, 269, 301, 335, 371, 408, 447, 488, 531, 576, 623, 672, 722, 774, 828, 884, 942, 1002, 1064, 1128, 1193, 1260, 1329, 1400, 1473, 1548, 1625, 1704, 1785, 1867, 1951, 2037, 2125, 2215, 2307, 2401, 2497, 2595, 2695, 2796, 2899, 3004, 3111, 3220 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) = the sum of the n highest entries in the projection of the n-th tetrahedron or tetrahedral number (e.g. a(7) = 7+6+6+5+5+5+4+4). a(n) is a sharp upper bound for the value of a gamma-labeling of a graph with n edges. (cf. Bullington) LINKS Grady D. Bullington, The Connell Sum Sequence, J. Integer Seq. 10 (2007), Article 07.2.6. (includes direct formula for a(n)) Ian Connell, Elementary Problem E1382, American Mathematical Monthly, v. 66, no. 8 (October, 1959), p. 724. Douglas E. Iannucci and Donna Mills-Taylor, On Generalizing the Connell Sequence, J. Integer Sequences, Vol. 2, 1999, #99.1.7. FORMULA a(n) = (n-th triangular number)-n+(n-th partial sum of A122797). Set R=Round(Sqrt(2*n),0), then a(n) = n^2+n-R*((6*n+1)-R^2)/6. - Gerald Hillier, Nov 29 2009 CROSSREFS Cf. A001614, A045928, A045929, A045930. Cf. A122794, A122795, A122796, A122797, A122798, A122799, A122800. Sequence in context: A025713 A022791 A025742 * A062714 A039677 A011899 Adjacent sequences:  A122790 A122791 A122792 * A122794 A122795 A122796 KEYWORD nonn,easy AUTHOR Grady Bullington (bullingt(AT)uwosh.edu), Sep 14 2006 STATUS approved

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Last modified August 20 03:33 EDT 2019. Contains 326139 sequences. (Running on oeis4.)