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Smallest prime p, such that |A000040(n)-p| is of the form 2^k.
1

%I #7 Jan 06 2024 22:03:07

%S 3,2,3,3,3,5,13,3,7,13,23,5,37,11,31,37,43,29,3,7,41,47,19,73,89,37,

%T 71,43,101,97,131,3,73,11,151,23,29,131,103,109,163,53,127,191,181,71,

%U 83,191,163,101,229,223,113,283,193,7,13,239,149,277,251,37,179,307,281,61

%N Smallest prime p, such that |A000040(n)-p| is of the form 2^k.

%H Ray Chandler, <a href="/A130970/b130970.txt">Table of n, a(n) for n=1..6736</a>

%o (Scheme:) (define (A130970 n) (let ((p1 (A000040 n))) (let loop ((i 1)) (cond ((pow2? (abs (- p1 (A000040 i)))) (A000040 i)) (else (loop (+ i 1)))))))

%o (define (pow2? n) (and (> n 0) (zero? (A004198bi n (- n 1)))))

%Y Cf. A000040, A130971.

%K nonn

%O 1,1

%A _Antti Karttunen_, Jun 19 2007

%E Extended by _Ray Chandler_, Aug 06 2010