

A282171


Singledigit numbers in the order in which they first appear in the decimal expansion of e, followed by the twodigit numbers in the order in which they appear, then the threedigit numbers, and so on.


2



2, 7, 1, 8, 4, 5, 9, 0, 3, 6, 27, 71, 18, 82, 28, 81, 84, 45, 59, 90, 52, 23, 35, 53, 36, 60, 87, 74, 47, 13, 26, 66, 62, 24, 49, 97, 77, 75, 57, 72, 70, 93, 69, 99, 95, 96, 67, 76, 40, 63, 30, 54, 94, 38, 21, 17, 78, 85, 25, 51, 16, 64, 42, 46, 39, 91, 19
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OFFSET

1,1


COMMENTS

Note that (except for 0 itself), numbers may not begin with 0. So that when we reach ...459045..., this contributes 90 to the sequence but not "04".  N. J. A. Sloane, Feb 08 2017


LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..10000


EXAMPLE

From Michael De Vlieger, Feb 09 2017: (Start)
Consider the decimal expansion of e=2.718281828459045235360...
The first 4 terms are 2,7,1,8 since these single digits appear in that order above. We do not encounter a different digit till we reach 4,5,9,0, thus these follow the first four in the sequence. We encounter 3 next, and finally 6 and have found all the single digits in the expansion.
a(11)=27 because we find the twodigit group "27" first, followed by a(12)=71, etc. until we exhaust the 90 possible twodigit groups that do not start with a zero.
a(101)=271 because we find the threedigit group "271" first, followed by a(102)=718, etc. until we exhaust the 900 possible 3digit groups that do not have leading zeros, etc. (End)


MATHEMATICA

e = First@ RealDigits@ N[E, 10^6]; MapIndexed[10^(First@ #2  1)  1  Boole[First@ #2 == 1] + Flatten@ Values@ KeySort@ PositionIndex@ #1 &, Table[SequencePosition[e, IntegerDigits@ k][[1, 1]], {n, 4}, {k, If[n == 1, 0, 10^(n  1)], 10^n  1}]] (* Michael De Vlieger, Feb 09 2017, Version 10.1 *)


CROSSREFS

Cf. A001113, A105177 (analog for Pi), A105178.
Sequence in context: A198128 A094121 A105178 * A112257 A248684 A175728
Adjacent sequences: A282168 A282169 A282170 * A282172 A282173 A282174


KEYWORD

nonn,base,look


AUTHOR

Bobby Jacobs, Feb 07 2017


EXTENSIONS

Edited by N. J. A. Sloane, Feb 08 2017
a(5), a(6), a(9), and a(10) inserted by Bobby Jacobs, Feb 09 2017
More terms from Michael De Vlieger, Feb 09 2017


STATUS

approved



