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 A173669 Numbers n which divide number of groups of order <= n (A063756). 1

%I

%S 1,2,3,12,26,31,84,119,248,1107,1543,1683

%N Numbers n which divide number of groups of order <= n (A063756).

%C No other terms up to 2047. - _Eric M. Schmidt_, Feb 10 2013

%F (k: k | A063756(k)} == (k: k | SUM[i=1..k] A000001(i)}.

%e a(1) = 1 because 1 divides (the number of groups of order <= 1) = (number of groups of order 1) = 1.

%e a(4) = 12 because 12 divides (the number of groups of order <= 12) = 24.

%e a(5) = 26 because 26 divides (the number of groups of order <= 26) = 78 = 3 * 26.

%e a(6) = 31 because 31 divides (the number of groups of order <= 31) = 93 = 3 * 31.

%o (GAP) A173669 := function(max) local n, res, i; n := 0; res := []; for i in [1..max] do n := n + NrSmallGroups(i); if n mod i = 0 then Add(res, i); fi; od; return res; end; # _Eric M. Schmidt_, Feb 10 2013

%Y Cf. A000001, A063756.

%K nonn,more

%O 1,2

%A _Jonathan Vos Post_, Nov 24 2010

%E More terms from _Eric M. Schmidt_, Feb 10 2013

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Last modified August 3 08:21 EDT 2021. Contains 346435 sequences. (Running on oeis4.)