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 A339816 #10 Dec 20 2020 16:45:04 %S A339816 1,2,4,5,8,9,12,14,16,18,21,32,64,65,68,72,84,128,129,132,136,138,141, %T A339816 145,159,170,192,204,208,256,258,261,324,385,448,462,512,513,515,516, %U A339816 520,536,576,578,581,640,705,723,776,908,912,1024,1036,1040,1049,1160,1172,1280,1352,1537,1600,1609,1666,1732,1795,2048 %N A339816 Numbers k for which A339814(k) >= A339822(k). %C A339816 Terms of (1/2)*A048675(A339817(i)), for i = 2.., sorted into ascending order. %C A339816 First occurrences of terms with binary weight (A000120) w = 1..19 are at n=1, 4, 8, 23, 50, 25, 125, 136, 176, 502, 749, 1142, 791, 1882, 2913, 4327, 17979, 16991, 12441. The terms themselves are: 1, 5, 14, 141, 908, 159, 8921, 9948, 18390, 175449, 400237, 1223389, 441805, 3234271, 28743379, 53892047, 1631024969, 1331412056, 725475951. %H A339816 Antti Karttunen, <a href="/A339816/b339816.txt">Table of n, a(n) for n = 1..19468</a> %o A339816 (PARI) %o A339816 A019565(n) = { my(m=1, p=1); while(n>0, p = nextprime(1+p); if(n%2, m *= p); n >>= 1); (m); }; %o A339816 isA339816(n) = { my(x=A019565(2*n)); (valuation(eulerphi(x),2)<=valuation(x-1,2)); }; %Y A339816 Positions of zeros and negative terms in A339815. %Y A339816 Cf. A000010, A000120, A007814, A019565, A048675, A339814, A339817, A339822. %Y A339816 Cf. A000079 (a subsequence). %K A339816 nonn %O A339816 1,2 %A A339816 _Antti Karttunen_, Dec 19 2020