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 A165468 #6 Jan 13 2024 13:06:41 %S A165468 0,1,3,5,7,9,11,13,17,19,21,23,27,29,35,37,39,41,45,47,49,53,57,59,63, %T A165468 65,67,71,75,77,81,83,89,95,97,99,101,107,109,111,113,117,119,125,127, %U A165468 129,131,133,137,139,147,149,153,155,161,165,167,169,173,179,185,187 %N A165468 a(n) = (A165469(n)-3)/4. %o A165468 (MIT/GNU Scheme) %o A165468 ; with MATCHING-POS macro by AK %o A165468 (define A165468 (MATCHING-POS 1 0 (lambda (n) (let ((w (A004767 n)) (hp (A005408 n))) (let loop ((i 1) (s 1)) (cond ((<= s 0) #f) ((>= i hp) #t) (else (loop (1+ i) (+ s (jacobi-symbol (1+ i) w)))))))))) %Y A165468 Subset of A095274. Cf. A165607. %K A165468 nonn %O A165468 1,3 %A A165468 _Antti Karttunen_, Oct 06 2009