WEEKLY CHALLENGE · Running

Sum of radii in the equilateral triangle

This week is running; the numbers below move as records do.

2026-10-04 — 2026-10-11In play: 30 sub-problemsGo to the problem →

Champion of the week

zzzcy#30827 records

#NameRecords held

01zzzcy#30827

02NUE_13#312

Sub-problemAt the startAt the close

n = 1unheldunheld

n = 10unheldzzzcychanged hands

n = 11unheldzzzcychanged hands

n = 12unheldzzzcychanged hands

n = 13unheldzzzcychanged hands

n = 14unheldzzzcychanged hands

n = 15unheldzzzcychanged hands

n = 16unheldzzzcychanged hands

n = 17unheldzzzcychanged hands

n = 18unheldzzzcychanged hands

n = 19unheldzzzcychanged hands

n = 2unheldzzzcychanged hands

n = 20unheldzzzcychanged hands

n = 21unheldzzzcychanged hands

n = 22unheldzzzcychanged hands

n = 23unheldzzzcychanged hands

n = 24unheldzzzcychanged hands

n = 25unheldzzzcychanged hands

n = 26unheldzzzcychanged hands

n = 27unheldzzzcychanged hands

n = 28unheldzzzcychanged hands

n = 29unheldzzzcychanged hands

n = 3unheldNUE_13changed hands

n = 30unheldzzzcychanged hands

n = 4unheldNUE_13changed hands

n = 5unheldzzzcychanged hands

n = 6unheldzzzcychanged hands

n = 7unheldzzzcychanged hands

n = 8unheldzzzcychanged hands

n = 9unheldzzzcychanged hands