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A357379 a(n) = A357378(floor(n/2)) * A357378(n).

%I A357379 #16 Sep 29 2022 03:25:44
%S A357379 1,2,4,6,8,10,3,9,12,16,5,15,7,11,18,21,24,27,20,28,13,14,30,33,35,42,
%T A357379 22,44,36,48,49,56,32,40,45,54,25,50,63,70,26,39,84,98,60,80,55,66,65,
%U A357379 75,72,78,34,38,52,64,90,96,88,104,77,91,112,120,68,76,85
%N A357379 a(n) = A357378(floor(n/2)) * A357378(n).
%C A357379 This sequence is a bijection from the nonnegative integers to the positive integers with inverse A357396 (see comments in A357378).
%H A357379 Rémy Sigrist, <a href="/A357379/b357379.txt">Table of n, a(n) for n = 0..10000</a>
%H A357379 Rémy Sigrist, <a href="/A357379/a357379.png">Density plot of the first 10000000 terms</a>
%H A357379 Rémy Sigrist, <a href="/A357379/a357379.txt">C program</a>
%H A357379 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%e A357379 a(5) = A357378(floor(5/2)) * A357378(5) = A357378(2) * A357378(5) = 2 * 5 = 10.
%o A357379 (C) See Links section.
%o A357379 (Python)
%o A357379 from itertools import count, islice
%o A357379 def agen(): # generator of terms
%o A357379     alst, disallowed = [1], {1}; yield 1
%o A357379     for n in count(1):
%o A357379         ahalf, k = alst[n//2], 1
%o A357379         while ahalf*k in disallowed: k += 1
%o A357379         an = k; yield ahalf*an; alst.append(an); disallowed.add(ahalf*an)
%o A357379 print(list(islice(agen(), 67))) # _Michael S. Branicky_, Sep 26 2022
%Y A357379 Cf. A357378, A357396 (inverse).
%K A357379 nonn
%O A357379 0,2
%A A357379 _Rémy Sigrist_, Sep 26 2022