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A038993
Number of sublattices of index n in generic 6-dimensional lattice.
12
1, 63, 364, 2667, 3906, 22932, 19608, 97155, 99463, 246078, 177156, 970788, 402234, 1235304, 1421784, 3309747, 1508598, 6266169, 2613660, 10417302, 7137312, 11160828, 6728904, 35364420, 12714681, 25340742, 25095280, 52294536, 21243690, 89572392, 29583456
OFFSET
1,2
REFERENCES
Michael Baake, "Solution of the coincidence problem in dimensions d <= 4", in R. V. Moody, ed., Math. of Long-Range Aperiodic Order, Kluwer 1997, pp. 9-44.
FORMULA
f(Q, n) = Sum_{d|n} d*f(Q-1, d); here Q=6.
Multiplicative with a(p^e) = product (p^(e+k)-1)/(p^k-1), k=1..5.
Dirichlet g.f.: zeta(s)*zeta(s-1)*zeta(s-2)*zeta(s-3)*zeta(s-4)*zeta(s-5). Dirichlet convolution of A038992 with A000584. - R. J. Mathar, Mar 31 2011
Sum_{k=1..n} a(k) ~ c * n^6, where c = Pi^12*zeta(3)*zeta(5)/3061800 = 0.376266... . - Amiram Eldar, Oct 19 2022
MATHEMATICA
f[p_, e_] := Product[(p^(e + k) - 1)/(p^k - 1), {k, 1, 5}]; a[1] = 1; a[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 100] (* Amiram Eldar, Aug 29 2019 *)
CROSSREFS
KEYWORD
nonn,mult
EXTENSIONS
Offset changed from 0 to 1 by R. J. Mathar, Mar 31 2011
More terms from Amiram Eldar, Aug 29 2019
STATUS
approved