login
A269795
Number of similarity classes of vectors with minimal Ducci period n.
1
2, 0, 6, 2, 30, 24, 126, 28, 504, 480, 2046, 990, 8190, 8064, 32730, 4064, 131070, 130536, 524286, 261630, 2097018, 2095104, 8388606, 2096100, 33554400, 33546240, 134217216, 67100670, 536870910, 536837640, 2147483646, 134213632, 8589932538, 8589803520, 34359738210
OFFSET
1,1
LINKS
Ron Brown and Jonathan L. Merzel, The number of Ducci sequences with given period, Fibonacci Quart. 45 (2007), no. 2, 115-121.
MATHEMATICA
a[n_] := DivisorSum[n, MoebiusMu[n/#] * 2^(#-IntegerExponent[#, 2]) &]; Array[a, 35] (* Amiram Eldar, Aug 24 2023 *)
PROG
(PARI) a(n) = sumdiv(n, d, moebius(n/d)*2^(d-valuation(d, 2)));
CROSSREFS
Sequence in context: A294779 A049257 A054877 * A372016 A095834 A106828
KEYWORD
nonn
AUTHOR
Michel Marcus, Mar 05 2016
STATUS
approved