cp's OEIS Frontend

A324339 a(n) = A246707(A005940(1+n)), where A005940 is the Doudna sequence, and A246707 is the expansion of phi(-q) * phi(-q^2) * phi(-q^3) * phi(-q^6) in powers of q.

%I A324339 #6 Feb 24 2019 17:51:56
%S A324339 -2,-2,2,6,4,-14,-2,6,0,-12,-4,42,2,-50,2,6,-8,-16,0,36,0,-84,4,42,14,
%T A324339 -62,-2,150,-24,-158,-2,6,4,-24,8,48,16,-112,0,36,0,-96,0,252,0,-300,
%U A324339 -4,42,-10,-114,-14,186,-28,-434,2,150,0,-312,24,474,38,-482,2,6,-4,-28,-4,72,-8,-168,-8,48,0,-144,-16,336,8,-400,0,36,16
%N A324339 a(n) = A246707(A005940(1+n)), where A005940 is the Doudna sequence, and A246707 is the expansion of phi(-q) * phi(-q^2) * phi(-q^3) * phi(-q^6) in powers of q.
%H A324339 Antti Karttunen, <a href="/A324339/b324339.txt">Table of n, a(n) for n = 0..1505</a>
%H A324339 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A324339 a(n) = A246707(A005940(1+n)).
%o A324339 (PARI)
%o A324339 A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ From A005940
%o A324339 A246707(n) = { local(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x + A)^2 * eta(x^2 + A) * eta(x^3 + A)^2 * eta(x^6 + A) / (eta(x^4 + A) * eta(x^12 + A)), n)); }; \\ From A246707
%o A324339 A324339(n) = A246707(A005940(1+n));
%Y A324339 Cf. A005940, A246707.
%Y A324339 Cf. also A323915, A324335, A324336, A324340.
%K A324339 sign
%O A324339 0,1
%A A324339 _Antti Karttunen_, Feb 23 2019