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 A285705 a(n) =  2*n - A285703(n) = 2*n - A000203(A064216(n)). 5

%I

%S 1,1,2,2,3,4,2,4,4,2,4,4,13,13,6,2,10,12,6,4,4,2,18,4,19,10,6,24,4,6,

%T 2,22,18,6,10,4,2,37,30,6,51,4,30,16,6,20,4,24,8,44,4,2,34,4,2,16,4,

%U 36,34,36,65,10,86,14,4,4,26,76,6,2,10,48,50,55,10,2,56,36,6,16,42,6,70,4,37,46,6,98,16,6,2,4,58,76,100,10,2,52,4,2,16,60,54

%N a(n) = 2*n - A285703(n) = 2*n - A000203(A064216(n)).

%C Question: Are all terms positive?

%C For listening: fast tempo and percussive instrument, default "modulo 88" pitch mapping, all 10000 terms.

%H Antti Karttunen, <a href="/A285705/b285705.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = 2*n - A285703(n) = 2*n - A000203(A064216(n)).

%t Table[2 n - DivisorSigma[1, #] &@ If[n == 1, 1, Apply[Times, FactorInteger[2 n - 1] /. {p_, e_} /; p > 2 :> NextPrime[p, -1]^e]], {n, 103}] (* _Michael De Vlieger_, Apr 26 2017 *)

%o (Scheme) (define (A285705 n) (- (* 2 n) (A285703 n)))

%Y Cf. A000203, A033879, A064216, A285703, A285704.

%K nonn,hear

%O 1,3

%A _Antti Karttunen_, Apr 26 2017

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Last modified June 24 12:30 EDT 2021. Contains 345416 sequences. (Running on oeis4.)