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Recamán Sequence

The sequence is defined as follows:
  • The first term is 0
  • The jumps to each subsequent term are 1, 2, 3, 4, ...
  • These jumps might be forwards or backwards
  • If a jump backwards gives a positive term that hasn't yet been in the sequence, jump backwards
  • If a backwards jump would give a negative term or a repeated term, jump forwards
Press "start" to watch the sequence unfold. Successive terms of the sequence are linked by semicircles. You can zoom in/out before pressing start to see less/more. What questions come to mind? For more details, head to the OEIS page or watch this Numberphile video by Alex Bellos.