This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A130970 #10 Jul 24 2025 19:11:55 %S A130970 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 A130970 71,43,101,97,131,3,73,11,151,23,29,131,103,109,163,53,127,191,181,71, %U A130970 83,191,163,101,229,223,113,283,193,7,13,239,149,277,251,37,179,307,281,61 %N A130970 Smallest prime p, such that |A000040(n)-p| is of the form 2^k. %H A130970 Ray Chandler, <a href="/A130970/b130970.txt">Table of n, a(n) for n=1..6736</a> %o A130970 (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 A130970 (define (pow2? n) (and (> n 0) (zero? (A004198bi n (- n 1))))) %Y A130970 Cf. A000040, A130971. %K A130970 nonn %O A130970 1,1 %A A130970 _Antti Karttunen_, Jun 19 2007 %E A130970 Extended by _Ray Chandler_, Aug 06 2010