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A277827
Digits that appear twice consecutively in the decimal expansion of Pi, in order of appearance.
0
3, 8, 9, 4, 9, 1, 6, 4, 5, 2, 1, 1, 1, 5, 5, 4, 2, 4, 8, 6, 3, 4, 3, 6, 6, 3, 0, 6, 5, 8, 8, 0, 1, 3, 8, 6, 1, 3, 1, 1, 1, 4, 9, 8, 2, 1, 3, 3, 4, 6, 2, 7, 6, 0, 0, 7, 7, 7, 4, 2, 2, 9, 1, 4, 7, 7, 9, 1, 9, 9, 9, 9, 9, 9, 4, 5, 2, 3, 4, 1, 8, 0, 0, 8, 3, 7, 6, 5, 1, 8, 7, 7, 2, 6, 0, 6, 1, 1, 8, 3
OFFSET
1,1
COMMENTS
A digit d of Pi is in this sequence iff A000796(i) = A000796(i+1), where i is the index of d in A000796. - Felix Fröhlich, Nov 01 2016
FORMULA
a(n) = A000796(A049514(n)).
EXAMPLE
Pi=3.14159265358979323846264(33)83279502(88)41971693(99)3751058209749(44)592307816406286208(99)8628034825342(11)70679...
Therefore, this sequence starts 3, 8, 9, 4, 9, 1.
PROG
(PARI) pidigit(n) = floor(Pi*10^n) - 10*floor(Pi*10^(n-1))
terms(n) = my(k=1, i=0); while(1, if(pidigit(k)==pidigit(k+1), print1(pidigit(k), ", "); i++); if(i==n, break); k++)
/* Print initial 100 terms as follows */
terms(100) \\ Felix Fröhlich, Nov 01 2016
CROSSREFS
Sequence in context: A177272 A010630 A197811 * A011276 A021882 A079591
KEYWORD
nonn,base
AUTHOR
Bobby Jacobs, Nov 01 2016
STATUS
approved