2^(4*n + 3)). The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Sarkar, Souradip and Gomony, Manil Dev. Quater-imaginary base for complex number
Sequence A003173 (Heegner numbers: imaginary quadratic fields with unique factorization (or class number 1).). The On-Line Encyclopedia of Integer Sequences
(编). Sequence A003173 (Heegner numbers: imaginary quadratic fields with unique factorization). The On-Line Encyclopedia of Integer Sequences. OEIS Foundation