login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A282171 Single-digit numbers in the order in which they first appear in the decimal expansion of e, followed by the two-digit numbers in the order in which they appear, then the three-digit 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 (list; graph; refs; listen; history; text; internal format)
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 two-digit group "27" first, followed by a(12)=71, etc. until we exhaust the 90 possible two-digit groups that do not start with a zero.

a(101)=271 because we find the three-digit group "271" first, followed by a(102)=718, etc. until we exhaust the 900 possible 3-digit 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 19 22:28 EDT 2018. Contains 316378 sequences. (Running on oeis4.)