This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A038992 Sublattices of index n in generic 5-dimensional lattice. 4
 1, 31, 121, 651, 781, 3751, 2801, 11811, 11011, 24211, 16105, 78771, 30941, 86831, 94501, 200787, 88741, 341341, 137561, 508431, 338921, 499255, 292561, 1429131, 508431, 959171, 925771, 1823451, 732541, 2929531, 954305, 3309747, 1948705, 2750971, 2187581, 7168161, 1926221 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES M. Baake, "Solution of coincidence problem...", in R. V. Moody, ed., Math. of Long-Range Aperiodic Order, Kluwer 1997, pp. 9-44. LINKS G. C. Greubel, Table of n, a(n) for n = 1..5000 M. Baake, N. Neumarker, A Note on the Relation Between Fixed Point and Orbit Count Sequences, JIS 12 (2009) 09.4.4, Section 3. FORMULA f(Q, n) = Sum_{d|n} d*f(Q-1, d); here Q=5. Multiplicative with a(p^e) = Product_{k=1..4} (p^(e+k)-1)/(p^k-1). Dirichlet g.f. zeta(s)*zeta(s-1)*zeta(s-2)*zeta(s-3)*zeta(s-4). Dirichlet convolution of A038991 with A000583. - R. J. Mathar, Mar 31 2011 MATHEMATICA a[n_] := DivisorSum[n, #*DivisorSum[#, #*DivisorSum[#, #*DivisorSum[#, # &] &] &] &]; Array[a, 50] (* Jean-François Alcover, Dec 02 2015, after Joerg Arndt *) PROG (PARI) a(n)=sumdiv(n, x, x * sumdiv(x, y, y * sumdiv(y, z, z * sumdiv(z, w, w ) ) ) ); /* Joerg Arndt, Oct 07 2012 */ CROSSREFS Cf. A001001. Sequence in context: A158558 A160893 A202994 * A068021 A131992 A042884 Adjacent sequences:  A038989 A038990 A038991 * A038993 A038994 A038995 KEYWORD nonn,mult AUTHOR EXTENSIONS Offset changed from 0 to 1 by R. J. Mathar, Mar 31 2011 More terms from Joerg Arndt, Oct 07 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 23 05:03 EDT 2019. Contains 323508 sequences. (Running on oeis4.)