(33s): OEIS A1614, Connell sequence, & A122793, A171152, A118011

[John Keith]

That is an impressively small program, especially considering that it returns all 4 values. But then I noticed your name on the formulas on the OEIS pages.

Here is a program for the HP 49 and 50 using ListExt 1.3 which works in a completely different way. Given a number n on the stack, the program returns a list of the first n*(n+1)/2 terms of the Connell sequence A001614. With an input of 50, the program returns a list of 1275 numbers in about 2.1 seconds on my 50g.

Code:


\<< LSEQ
  { DUP 1 - SQ 1 + 2 ROT LASEQ
  } LMAP LXIL
\>>

For the partial sums A122793, follow the program with { + } LSCAN.