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A366377 Number of branching factorizations of the primorial inflation of n. 4

%I #15 Jan 03 2024 11:02:41

%S 0,1,3,2,19,11,207,5,62,113,3211,45,64383,1709,911,15,1581259,345,

%T 45948927,645,17753,33797,1541641771,195,9332,822821,2405,12405,

%U 58645296063,6525,2494091717899,51,428309,23765093,223031,1890,117258952478847,793795349,12293957,3585,6038838138717931,154605,338082244882740543,296805

%N Number of branching factorizations of the primorial inflation of n.

%C Conjecture: Sequence is injective (no value occurs more than once). If true, then also the conjecture given in A277120 is correct. See also A366884.

%H Antti Karttunen, <a href="/A366377/b366377.txt">Table of n, a(n) for n = 1..121</a>

%F a(n) = A277120(A108951(n)).

%F a(n) = A366884(A329901(n)).

%F For n >= 1, a(2^n) = A007317(n), a(A000040(n)) = A052886(n).

%o (PARI)

%o A002110(n) = prod(i=1,n,prime(i));

%o A108951(n) = { my(f=factor(n)); prod(i=1, #f~, A002110(primepi(f[i, 1]))^f[i, 2]) }; \\ From A108951

%o memoA277120 = Map();

%o A277120(n) = if(1==n,0,my(v); if(mapisdefined(memoA277120,n,&v), v, v = 1+sumdiv(n,d,if((1==d)||(d*d)>n,0,if((d*d)==n,1,2)*A277120(d)*A277120(n/d))); mapput(memoA277120,n,v); (v)));

%o A366377(n) = A277120(A108951(n));

%Y Cf. A000040, A007317, A052886, A108951, A277120.

%Y Permutation of A366884.

%K nonn

%O 1,3

%A _Antti Karttunen_, Dec 31 2023

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Last modified August 8 18:48 EDT 2024. Contains 375023 sequences. (Running on oeis4.)