A277827 Digits that appear twice consecutively in the decimal expansion of Pi, in order of appearance.

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

Author

Bobby Jacobs, Nov 01 2016

Keywords

• nonn
• base

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

Examples

			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.
		

Crossrefs

Cf. A000796, A049514.

Programs

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

Formula

a(n) = A000796(A049514(n)).