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Numbers that occur exactly once in the odd bisection of A371094.
4

%I #9 Apr 26 2024 10:59:26

%S 45,69,93,141,165,189,237,261,285,333,357,381,429,453,477,525,549,573,

%T 621,645,669,717,725,741,765,813,837,861,909,933,957,1005,1029,1053,

%U 1101,1109,1125,1149,1197,1221,1245,1293,1317,1341,1389,1413,1437,1485,1493,1509,1533,1581,1605,1629,1677,1701,1725,1773,1797

%N Numbers that occur exactly once in the odd bisection of A371094.

%C Numbers that occur exactly once in array A371100.

%H Antti Karttunen, <a href="/A372291/b372291.txt">Table of n, a(n) for n = 1..25365</a>

%e 45 is present because A371094(k) = 45 for no other odd number than k=7.

%o (PARI)

%o A371094(n) = { my(m=1+3*n, e=valuation(m,2)); ((m*(2^e)) + (((4^e)-1)/3)); };

%o isA372291(n) = if(!(n%2),0,my(c=0); forstep(k=1,n,2,if(A371094(k)==n,c++;if(c>1,return(0)))); (c));

%Y Cf. A371094, A371100.

%Y Setwise difference A372290 \ A372292.

%K nonn

%O 1,1

%A _Antti Karttunen_, Apr 26 2024