The centred triangular numbers

HTTP/1.1 500 Internal Server Error Date: Fri, 26 Apr 2024 05:00:38 GMT Server: CL-HTTP/70.217 (LispWorks; 2.1.7) Connection: close Content-Type: text/html; charset=ISO-8859-1 Transfer-Encoding: chunked Internal Server Error

Internal Server Error

No applicable methods for #<STANDARD-GENERIC-FUNCTION NUMBERS::APPLY-FN 22E249B2> with args (0 0 NIL 0 :QUADRATIC (1 3/2 3/2))

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