RE : [math-fun] First differences spoiler

S = one, nine, nine, five, five, nine, nine, five, five, nine, one, three, thirteen, seventeen, one, three, thirteen, seventeen, nine, five, five, nine, nine, five, five, nine, one, three, thirteen, seventeen, one, three, thirteen, seventeen,... . . . Ok, answer is... . . . O N E N I N E N I N E F I V E F I V E 1 9 9 5 5 9 9 5 5 9 1 3 13 17 1 3 13 17 --> first (letters rank) diff. is seq. itself

Best, E.