OFFSET
1,1
COMMENTS
Equals 2^(2 - d) * 3^(d - 1), where d = lim_{k->infinity} (1/k)*Sum_{i=1..k} A293630(i) = 1.275261... (see A296564).
See comments from Jon E. Schoenfield on A296564 for explanation of PARI program.
Is this number transcendental?
LINKS
Iain Fox, Table of n, a(n) for n = 1..20000
EXAMPLE
Equals 2.2361513774687490396627784066120440739114649924...
Values evaluated with A291481(k):
k = 1: 4^(1/1) = 4
k = 2: 7^(1/2) = 2.645751311064590590...
k = 3: 13^(1/3) = 2.351334687720757489...
k = 4: 37^(1/4) = 2.466325714559660444...
k = 5: 73^(1/5) = 2.358655818240735626...
k = 6: 145^(1/6) = 2.292070651723655173...
...
k = infinity: A291481(k)^(1/k) = 2.236151377468749039...
PROG
(PARI) gen(build) = {
my(S = [1, 2], n = 2, t = 3, L, nPrev, E);
for(j = 1, build, L = S[#S]; n = n*(1+L)-L; t = t*(1+L)-L^2; nPrev = #S; for(r = 1, L, for(i = 1, nPrev-1, S = concat(S, S[i]))));
E = S;
for(j = build + 1, build + #E, L = E[#E+1-(j-build)]; n = n*(1+L)-L; t = t*(1+L)-L^2);
return(2^(2 - t/n)*3^(t/n - 1))
} \\ (gradually increase build to get more precise answers)
CROSSREFS
KEYWORD
cons,nonn
AUTHOR
Iain Fox, Jan 07 2018
STATUS
approved