OFFSET
1,1
COMMENTS
Different from A060649.
Conjecture 1: a(n) > 0 for all n;
Conjecture 2: a(n) = o(n^2).
What's the next even term after a(20) = 776 and a(104) = 14024?
LINKS
Jianing Song, Table of n, a(n) for n = 1..488
FORMULA
For odd n, if a(n) > 0, then a(n) >= A060649(n). The smallest odd n such that the inequality is strict is n = 243.
EXAMPLE
The smallest k such that c(-k) = C_12 is k = 327, so a(12) = 327.
The smallest k such that c(-k) = C_16 is k = 407, so a(16) = 407.
The smallest k such that c(-k) = C_20 is k = 776, so a(20) = 776.
The smallest k such that c(-k) = C_243 is k = 38231, so a(243) = 38231.
PROG
(PARI) a(n) = if(n==1, 3, my(d=3); while(!isfundamental(-d) || quadclassunit(-d)[2]!=[n], d++); d)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jianing Song, May 08 2021
STATUS
approved