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A293829
Numbers k such that (d(k), d(k+1)) = (0,1) in the base-2 digits d(i) of Pi.
4
4, 7, 12, 19, 22, 24, 26, 30, 34, 39, 41, 44, 48, 54, 58, 61, 64, 69, 72, 77, 81, 86, 88, 92, 94, 104, 107, 115, 120, 123, 127, 130, 132, 135, 142, 145, 148, 156, 160, 164, 166, 169, 173, 180, 185, 189, 198, 204, 206, 210, 216, 218, 221, 226, 230, 235, 238
OFFSET
1,1
LINKS
EXAMPLE
This sequence together with A293828, A293830, and A293831 partition the positive integers.
(d(i)) = (1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0,...) = A004601, in which (0,1) first occurs as (a(4),a(5)).
MATHEMATICA
z = 100; s = StringJoin[Map[ToString, First[RealDigits[N[Pi, 10000], 2]]]];
Take[Map[#[[1]]&, StringPosition[s, "00"]], z] (* A293828 *)
Take[Map[#[[1]]&, StringPosition[s, "01"]], z] (* A293829 *)
Take[Map[#[[1]]&, StringPosition[s, "10"]], z] (* A293830 *)
Take[Map[#[[1]]&, StringPosition[s, "11"]], z] (* A293831 *)
(* Peter J. C. Moses, Oct 15 2017 *)
SequencePosition[RealDigits[Pi, 2, 300][[1]], {0, 1}][[All, 1]] (* Harvey P. Dale, Jan 18 2023 *)
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Clark Kimberling, Oct 20 2017
STATUS
approved