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 A276543 Triangle read by rows: T(n,k) = number of primitive (period n) n-bead bracelet structures using exactly k different colored beads. 15
 1, 0, 1, 0, 1, 1, 0, 2, 2, 1, 0, 3, 5, 2, 1, 0, 5, 13, 11, 3, 1, 0, 8, 31, 33, 16, 3, 1, 0, 14, 80, 136, 85, 27, 4, 1, 0, 21, 201, 478, 434, 171, 37, 4, 1, 0, 39, 533, 1849, 2270, 1249, 338, 54, 5, 1, 0, 62, 1401, 6845, 11530, 8389, 3056, 590, 70, 5, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,8 COMMENTS Turning over will not create a new bracelet. Permuting the colors of the beads will not change the structure. REFERENCES M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2] LINKS Andrew Howroyd, Table of n, a(n) for n = 1..1275 FORMULA T(n, k) = Sum_{d|n} mu(n/d) * A152176(d, k). EXAMPLE Triangle starts:   1   0  1   0  1   1   0  2   2    1   0  3   5    2    1   0  5  13   11    3    1   0  8  31   33   16    3   1   0 14  80  136   85   27   4  1   0 21 201  478  434  171  37  4 1   0 39 533 1849 2270 1249 338 54 5 1   ... PROG (PARI) \\ Ach is A304972 and R is A152175 as square matrices. Ach(n)={my(M=matrix(n, n, i, k, i>=k)); for(i=3, n, for(k=2, n, M[i, k]=k*M[i-2, k] + M[i-2, k-1] + if(k>2, M[i-2, k-2]))); M} R(n)={Mat(Col([Vecrev(p/y, n) | p<-Vec(intformal(sum(m=1, n, eulerphi(m) * subst(serlaplace(-1 + exp(sumdiv(m, d, y^d*(exp(d*x + O(x*x^(n\m)))-1)/d))), x, x^m))/x))]))} T(n)={my(M=(R(n)+Ach(n))/2); Mat(vectorv(n, n, sumdiv(n, d, moebius(d)*M[n/d, ])))} { my(A=T(12)); for(n=1, #A, print(A[n, 1..n])) } \\ Andrew Howroyd, Sep 20 2019 CROSSREFS Columns 1-6 are A063524, A056366, A056367, A056368, A056369, A056370. Partial row sums include A000046, A056362, A056363, A056364, A056365. Row sums are A276548. Cf. A276550, A152175, A152176, A107424, A137651, A276544, A304972. Sequence in context: A306754 A063250 A285308 * A107424 A155161 A185937 Adjacent sequences:  A276540 A276541 A276542 * A276544 A276545 A276546 KEYWORD nonn,tabl AUTHOR Andrew Howroyd, Apr 09 2017 STATUS approved

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Last modified September 25 06:32 EDT 2020. Contains 337335 sequences. (Running on oeis4.)