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n times the n-th digit of the decimal expansion of Pi.
0

%I #16 Jul 08 2021 00:47:31

%S 3,2,12,4,25,54,14,48,45,30,55,96,117,98,135,48,34,54,152,80,126,44,

%T 138,96,75,78,216,84,58,210,279,160,0,68,280,288,148,38,351,280,41,

%U 252,387,132,405,414,141,336,245,50,0,260,424,108,0,504,399,232,531

%N n times the n-th digit of the decimal expansion of Pi.

%H <a href="/index/Ph#Pi314">Index entries for sequences related to the number Pi</a>

%e The first digit of the decimal expansion of Pi is 3, so a(1) = 1*3 = 3.

%e The second digit of the decimal expansion of Pi is 1, so a(2) = 2*1 = 2.

%e The third digit of the decimal expansion of Pi is 4, so a(3) = 3*4 = 12.

%t Module[{nn=120,pid},pid=RealDigits[Pi,10,nn][[1]];Table[n pid[[n]],{n,nn}]]

%o (Python)

%o from sympy import S

%o def aupton(terms):

%o digits_of_pi = "0" + str(S.Pi.n(terms+1)).replace('.', '')

%o return [n*int(digits_of_pi[n]) for n in range(1, terms+1)]

%o print(aupton(59)) # _Michael S. Branicky_, Jul 08 2021

%Y Cf. A000796, A014976 (zeros), A053745 (fixed points).

%Y Cf. A053746, A053747, A053748, A053749, A053750, A053751, A053752, A053753.

%K base,nonn

%O 1,1

%A _Harvey P. Dale_, Jul 05 2021