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Graceful Pi-Way


GracefulPi-Way

The graceful pi-way is the path through the 15 states on the western and northern borders of the contiguous USA graph, stretching from California to Maine, in a particular graceful labeling. Its vertex labels are 31, 41, 59, 26, 53, 58, 97, 93, 23, 84, 62, 64, 33, 83, and 27, precisely the first 30 decimal digits of pi. T. Rokicki found the labeling in October 2020, and Knuth (2025, p. 18) describes it as a "graceful miracle." With apologies to Gordon Lightfoot's "Carefree Highway," the path is illustrated in red above.


See also

Contiguous USA Graph, Graceful Graph, Graceful Labeling, Pi Digits

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References

Knuth, D. E. §7.2.2.3 in The Art of Computer Programming, Vol. 4, Fascicle 7: Constraint Satisfaction. Boston, MA: Addison-Wesley, p. 18, 2025.

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Graceful Pi-Way

Cite this as:

Weisstein, Eric W. "Graceful Pi-Way." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/GracefulPi-Way.html

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