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 A213344 2-quantum transitions in systems of N>=2 spin 1/2 particles, in columns by combination indices. 3
 1, 6, 24, 4, 80, 40, 240, 240, 15, 672, 1120, 210, 1792, 4480, 1680, 56, 4608, 16128, 10080, 1008, 11520, 53760, 50400, 10080, 210, 28160, 168960, 221760, 73920, 4620, 67584, 506880, 887040, 443520, 55440, 792 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 COMMENTS For a general discussion, please see A213343. This a(n) is for double-quantum transitions (q = 2). It lists the flattened triangle T(2;N,k) with rows N = 2,3,... and columns N, k = 0..floor((N-2)/2). REFERENCES See A213343. LINKS Stanislav Sykora, Table of n, a(n) for n = 2..2501 Stanislav Sykora, T(2;N,k) with rows N=2,..,100 and columns k=0,..,floor((N-2)/2) FORMULA Set q = 2 in: T(q;N,k) = 2^(N-q-2*k)*binomial(N,k)*binomial(N-k,q+k). EXAMPLE For N=4, there are 4 second-quantum transitions with combination index 1: (0001,1110),(0010,1101),(0100,1011),(1000,0111). Starting rows of the triangle:   N | k = 0, 1, ..., floor((N-2)/2)   2 |   1   3 |   6   4 |  24   4   5 |  80  40   6 | 240 240 15 PROG (PARI) See A213343; set thisq = 2. CROSSREFS Cf. A051288 (q=0), A213343 (q=1), A213345 to A213352 (q=3..10). Cf. A001788 (first column), A002694 (row sums). Sequence in context: A194770 A052697 A293256 * A193429 A213278 A029592 Adjacent sequences:  A213341 A213342 A213343 * A213345 A213346 A213347 KEYWORD nonn,tabf AUTHOR Stanislav Sykora, Jun 09 2012 STATUS approved

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Last modified August 14 09:05 EDT 2018. Contains 313750 sequences. (Running on oeis4.)