[seqfan] Digit Spiral

[Eric Angelini]

(Inspired by another spiral just seen here)

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1) start to write on a grid the nonnegative integers so to form a spiral
   (one digit clockwise per unit-square);
2) make a pause for the last integer fitting perfectly in a [square of
   unit-squares] -- else proceed;
3) colour this last integer in yellow;
4) call S the sequence of yellow terms.

http://www.cetteadressecomportecinquantesignes.com/DigitSpiral.htm

Best,
É.