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A257246 Even bisection of A257244: a(n) = A257244(2n). 5


%S 2,3,3,3,3,5,3,3,3,5,7,7,3,3,7,3,5,3,5,5,11,3,13,3,13,5,11,3,7,3,13,3,

%T 13,3,5,5,11,23,3,7,3,7,3,7,3,31,3,7,13,3,7,5,7,3,31,31,3,13,41,5,3,7,

%U 19,3,7,41,41,3,19,7,29,5,3,13,11,5,3,19,3,5,5

%N Even bisection of A257244: a(n) = A257244(2n).

%H Antti Karttunen, <a href="/A257246/b257246.txt">Table of n, a(n) for n = 1..2047</a>

%H <a href="https://oeis.org/plot2a?name1=A257246&amp;name2=A257245&amp;tform1=untransformed&amp;tform2=untransformed&amp;shift=0&amp;radiop1=ratio&amp;drawpoints=true">Ratio a(n)/A257245(n) plotted with OEIS Plot2-script</a>

%F a(n) = A257244(2n).

%F a(n) = A020639(A256393(2n)). [Equally, the smallest prime factor of A256393(2n).]

%F Other identities and observations:

%F For all n >= 1, a(n) <= A257245(n).

%o (Scheme, alternative definitions)

%o (define (A257246 n) (A257244 (+ n n)))

%o (define (A257246 n) (A020639 (A256393 (+ n n))))

%Y Cf. A020639, A256393, A257244.

%Y Cf. also A257245 (the other bisection), A257247 (gives the positions where both bisections have the same value).

%K nonn

%O 1,1

%A _Antti Karttunen_, Apr 19 2015

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Last modified December 2 05:01 EST 2021. Contains 349437 sequences. (Running on oeis4.)