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%I #5 Oct 12 2017 03:17:41
%S 6,8,10,12,16,16,20,24,28
%N Minimum sum of absolute values of coefficients of a product of n binomials.
%C Consider polynomials of the form P(a_1, ..., a_n) = (1-x^{a_1})*...*(1-x^{a_n}), where a_i are positive integers. Let L(a_1, ..., a_n) be the sum of absolute values of the coefficients. Then a(n) = min { L(a_1, ..., a_n) : 1 <= a_1 <= ..., <= a_n }.
%C Upper bounds (probably not tight, except perhaps for a(12)) for the following terms are: 36, 44, 52, 52, 60, 68, 84, 96, 116, 130, 140, 156, 192, 188, 228, 262, 280, 316, 368, 344, 416, 440, 460, 456, 492, 584, 652, 688, 684, 734, 872, 902, 976, 988, 1136, 1176, 1224, 1328, 1448, 1632, 1544, 1596, 1712, 1728, 1840.
%H P. Borwein and C. Ingalls, <a href="http://www.cecm.sfu.ca/~pborwein/PAPERS/P98.pdf">The Prouhet-Tarry-Escott problem revisited</a>, L'Enseign. Math., 40 (1994), pp. 3-27.
%H M. Cipu, <a href="https://doi.org/10.1112/S1461157000001030">Upper bounds for norms of products of binomials</a>, LMS J. Comput. Math., 7 (2004), pp. 37-49.
%H R. Maltby, <a href="https://doi.org/10.1090/S0025-5718-97-00865-X">Pure product polynomials and the Prouhet-Tarry-Escott problem</a>, Math. Comp., 66 (1966), pp. 1323-1340.
%K nonn,more
%O 3,1
%A Mihai Cipu (mihai.cipu(AT)imar.ro), Mar 30 2004