1,2

The digits at position 1667 are "334", so, according to the strict definition of this sequence, a(33) is 1667, and a(34) is 1668. However, this would not enable a person to mark in bold-face the counting numbers within the digits of pi, which was the inspiration for this sequence. Surprisingly, if overlapping is not allowed, this changes only one element of the sequence. a(34) becomes 1700, and a(35) remains 1719. No other overlapping occurs within the first 100,000 decimal digits of Pi. - Graeme McRae (g_m(AT)mcraefamily.com), Mar 20 2005

Dave Andersen, The Pi-Search Page.

Bob Happelberg, Bob's Poetry Page for February 2005

Moving always to the right in the decimal expansion of Pi, the string "1" is found at position 1 counting from the first digit after the decimal point, the string "2" is found at position 6, the string "3" at position 6, the string "4" at position 19, etc.

p = ToString[ FromDigits[ RealDigits[ N[Pi - 3, 2600]][[1]]]]; lst = {0}; Do[a = StringPosition[p, ToString[n], 1][[1, 1]]; AppendTo[lst, a + lst[[ -1]]]; p = StringDrop[p, a], {n, 49}]; Rest[lst] (from Robert G. Wilson v Mar 19 2005)

(MAGMA) k := 3000; R := RealField(k); S := IntegerToString(Round(10^k*(-3 + Pi(R)))); Q := []; d := 0; for n in [1..49] do p:= Position(S, IntegerToString(n)); d+:=p; Append(~Q, d); S := Substring(S, p+1, #S-p); end for; Q; /* Klaus Brockhaus, Feb 15 2007 */

Cf. A000796, A078197, A014777 (another version).

Sequence in context: A078415 A023041 A118277 this_sequence A011988 A096546 A043103

Adjacent sequences: A103183 A103184 A103185 this_sequence A103187 A103188 A103189

nonn,base,easy

Suggested by Bob's Poetry Page. - Alonso Del Arte (alonso.delarte(AT)gmail.com), Mar 01 2005

More terms from Graeme McRae (g_m(AT)mcraefamily.com) and Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 19 2005