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 A324200 #16 Feb 19 2019 00:11:24 %S A324200 6,60,32752,137438953408 %N A324200 a(n) = 2^(A000043(n)-1) * ((2^A059305(n)) - 1), where A059305 gives the prime index of the n-th Mersenne prime, while A000043 gives its exponent. %C A324200 If there are no odd perfect numbers then these are the positions of zeros in A324185. %C A324200 The next term has 314 digits: %C A324200 11781361728633673532894774498354952494238773929196300355071513798753168641589311119865182769801300280680127783231251635087526446289021607771691249214388576215221396663491984443067742263787264024212477244347842938066577043117995647400274369612403653814737339068225047641453182709824206687753689912418253153056583680. %F A324200 a(n) = ((2^A000720(A000668(n)))-1) * 2^(A000043(n)-1) = ((2^A059305(n)) - 1) * 2^(A000043(n)-1). %F A324200 a(n) = A243071(A156552(A324201(n))) = A243071(A156552(A062457(A000043(n)))). %F A324200 If no odd perfect numbers exist, then a(n) = A243071(A000396(n)), and thus A007814(a(n)) = A007814(A000396(n)). %o A324200 (PARI) A324200(n) = (2^(A000043(n)-1))*((2^primepi(A000668(n)))-1); %Y A324200 Subsequence of A023758 and A324199. %Y A324200 Cf. A000043, A000396, A000668, A000720, A007814, A023758, A059305, A156552, A243071, A324185. %K A324200 nonn %O A324200 1,1 %A A324200 _Antti Karttunen_, Feb 18 2019