A175728 Decimal expansion of e written as a sequence of distinct positive integers.

2, 7, 1, 8, 28, 18, 284, 5, 90, 4, 52, 3, 53, 60, 287, 47, 13, 526, 6, 24, 9, 77, 57, 2470, 93, 69, 99, 59, 574, 96, 696, 76, 27, 72, 40, 766, 30, 35, 354, 75, 94, 571, 38, 21, 78, 525, 16, 64, 274, 2746, 63, 91, 93200, 305, 992, 181, 74, 135, 966, 290, 43, 572, 900, 33, 42

Offset

1,1

Comments

Inverse: 3, 1, 12, 10, 8, 19, 2, 4, 21, 119, 86, 166, 17, 154, 160, 47, 192, 6, 83, 214, ..., . - Robert G. Wilson v, Aug 22 2010

Links

Michael S. Branicky, Table of n, a(n) for n = 1..10000

Mathematica

rd = RealDigits[E, 10, 200][[1]]; lst = {}; f[n_] := Block[{k = 1}, While[a = FromDigits[ Take[ rd, k]]; MemberQ[lst, a] || rd[[k + 1]] == 0, k++ ]; AppendTo[ lst, a]; rd = Drop[rd, k]]; Array[f, 70]; lst (* Robert G. Wilson v, Aug 22 2010 *)

Prog

(Python)
from itertools import islice
from sympy import exp
def diggen():
    yield from map(int, str(exp(1).n(10**5))[:-1].replace(".", ""))
def agen(): # generator of terms
    g = diggen()
    aset, nextd = set(), next(g)
    while True:
        an, nextd = nextd, next(g)
        while an in aset or nextd == 0:
            an, nextd = int(str(an) + str(nextd)), next(g)
        yield an
        aset.add(an)
print(list(islice(agen(), 65))) # Michael S. Branicky, Mar 31 2022

Crossrefs

Cf. A001113, A064809.

Sequence in context: A282171 A112257 A248684 * A261390 A248676 A369445

Adjacent sequences: A175725 A175726 A175727 * A175729 A175730 A175731

Keyword

nonn,base

Author

Jason G. Wurtzel, Aug 19 2010

Extensions

More terms from Robert G. Wilson v, Aug 22 2010

Status

approved