NAL’s Double Cross Sequence

I Googled it. Nobody else has made this sequence up before. So it’s mine. I’m naming it after me. You heard it here first. I call it NAL’s Double Cross Sequence, and it goes like follows: 5, 21, 45, 105, 405, 525, 945, 945, 2205… (as far as I’ve calculated). And the description I’ve given […]