A074850 Partial products of successive digits in the decimal expansion of Pi.
3, 3, 12, 12, 60, 540, 1080, 6480, 32400, 97200, 486000, 3888000, 34992000, 244944000, 2204496000, 6613488000, 13226976000, 39680928000, 317447424000, 1269789696000, 7618738176000, 15237476352000, 91424858112000
Offset: 1
Examples
a(3)=12 because pi(1)=3, pi(1)=1, pi(3)=4 and a(3)=3*1*4=12.
Programs
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Mathematica
ppi={3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9, 3, 2, 3, 8, 4, 6, 2, 6, 4, 3, 3, 8, 3, 2, 7, 9, 5, 0, 2, 8}; Table[Product[ppi[[i]], {i, n}], {n, 1, 33}] Rest[FoldList[Times,1,RealDigits[Pi,10,30][[1]]]] (* Harvey P. Dale, Jan 23 2015 *)
Formula
a(n) = pi(1)*...*pi(n); pi(n)=A000796(n).
a(n) = A073055(n), n>0. - R. J. Mathar, Dec 15 2020
Comments