The next perfect pi-day

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gregorian · gregorian/yy-m-dd reads3141592653589π to 13 digits

to 09:26:53 your local time

Calendars shown

Pick which calendars appear below. Gregorian is the anchor — always shown.

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Dates are each calendar's own reading of the same day. Anchored to Gregorian.

  1. gregoriananchorgregorian/yy-m-dd31·4·15·92653589π·13
  2. holoceneholocene/yy-m-dd31·4·15·92653589π·13same day as Gregorian 2031-04-15
  3. julianjulian/yy-m-dd31·4·15·92653589π·13same day as Gregorian 2031-04-28 — julian runs 13 days behind Gregorian
  4. japanesejapanese/mm-dd-yy3·14·33·92653589π·13same day as Gregorian 2033-03-14
  5. persianpersian/mm-dd-yy3·14·15·92653589π·13same day as Gregorian 2036-06-03
  6. ethiopicethiopic/yy-m-dd31·4·15·92653589π·13same day as Gregorian 2038-12-24
  7. minguominguo/yy-m-dd31·4·15·92653589π·13same day as Gregorian 2042-04-15
  8. japanesejapanese/yy-m-dd49·4·15·92653589π·13same day as Gregorian 2049-04-15
  9. persianpersian/yy-m-dd31·4·15·92653589π·13same day as Gregorian 2052-07-05
  10. hebrewhebrew/mm-dd-yy3·14·15·92653589π·13same day as Gregorian 2054-12-15
  11. romanroman/mm-dd-yy3·14·15·92653589π·13same day as Gregorian 2062-03-27
  12. assyrianassyrian/mm-dd-yy3·14·15·92653589π·13same day as Gregorian 2065-03-14

Lifetime timeline

Every perfect pi-day from 2000 to 2226.

20002226

Collision search

Known witnesses, now with the CRT mechanics that determine how many collision classes survive.

Double πVerified

Historical double π

0215-03-14

Gregorian ∩ Julian

  • Gregorian3/14/15
  • Julian3/14/15
Double πVerified

Deep-future double π

2197415-03-14

Gregorian ∩ Tabular Hijri

  • Gregorian3/14/15
  • Tabular Hijri3/14/15
Witnesses / cycleN = 12
Mean interval3.54 million years
Supercycle15,531,572,070 days
gcd filtersGregorian / Tabular Hijri = 1
Triple πModel-dependent

Triple π witness

195360930015-03-14

Gregorian ∩ Tabular Hijri ∩ Persian 33-year model

  • Gregorian3/14/15
  • Tabular Hijri14 Rabi' al-awwal · year …15
  • Persian 33-year model14 Khordad · year …15
Witnesses / cycleN = 36
Mean interval142.37 billion years
Supercycle1,872,020,381,597,100 days
gcd filtersGregorian / Tabular Hijri = 1 · Gregorian / Persian 33-year model = 1 · Tabular Hijri / Persian 33-year model = 10

Model: Tabular Hijri + cyclic 33-year Persian arithmetic model

The gcd=10 compatibility filter is structural for these periods; N=36 and the exact witness are convention-dependent.

None yet inside the 2000–2226 window — the clean collisions are ancient or deep-future.