A021069 -id:A021069 - cp's OEIS frontend

A351474 Numbers m such that the largest digit in the decimal expansion of 1/m is 8.

7, 12, 14, 26, 28, 35, 48, 54, 55, 56, 63, 65, 70, 72, 78, 79, 93, 117, 120, 123, 125, 128, 140, 175, 176, 186, 192, 195, 205, 224, 239, 259, 260, 264, 280, 296, 312, 318, 328, 350, 372, 416, 432, 438, 448, 465, 480, 540, 542, 546, 548, 550, 555, 560, 572, 584, 594, 630, 632, 650, 675

Offset: 1

Bernard Schott and Robert G. Wilson v, Feb 19 2022

If k is a term, 10*k is also a term. First few primitive terms are 7, 12, 14, 26, 28, 35, 48, 54, 55, 56, 63, 65, 72, ...

The seven primes up to 2.7*10^8 are 7, 79, 239, 62003, 538987, 35121409, 265371653 (see comments in A333237, example section and Crossrefs).

			As 1/7 = 0.142857142857142857..., 7 is a term.
As 1/26 = 0.0384615384615384615..., 26 is another term.

Index entries for sequences related to decimal expansion of 1/n.

Similar with largest digit k: A333402 (k=1), A341383 (k=2), A350814 (k=3), A351470 (k=4), A351471 (k=5), A351472 (k=6), A351473 (k=7), this sequence (k=8), A333237 (k=9).
Cf. A333236.
Decimal expansion of: A020806 (1/7), A021058 (1/54), A021060 (1/56), A021067 (1/63), A021069 (1/65), A021083 (1/79), A021097 (1/93).

f[n_] := Union[ Flatten[ RealDigits[ 1/n][[1]] ]]; Select[Range@1500000, Max@ f@# == 8 &]

isok(m) = my(m2=valuation(m, 2), m5=valuation(m, 5)); vecmax(digits(floor(10^(max(m2,m5) + znorder(Mod(10, m/2^m2/5^m5))+1)/m))) == 8; \\ Michel Marcus, Feb 26 2022

from itertools import count, islice
from sympy import multiplicity, n_order
def A351474_gen(startvalue=1): # generator of terms >= startvalue
    for a in count(max(startvalue,1)):
        m2, m5 = (~a&a-1).bit_length(), multiplicity(5,a)
        k, m = 10**max(m2,m5), 10**n_order(10,a//(1<A351474_list = list(islice(A351474_gen(),20)) # Chai Wah Wu, May 02 2023

A333236(a(n)) = 8.

A021654 Decimal expansion of 1/650.

Original entry on oeis.org

0, 0, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1

Offset: 0

N. J. A. Sloane

A021069 shifted right. - R. J. Mathar, Oct 25 2008

Index entries for linear recurrences with constant coefficients, signature (1,0,-1,1).

Cf. A021069.

Join[{0,0},RealDigits[1/650,10,120][[1]]] (* or *) PadRight[{0,0},120,{4,6,1,5,3,8}] (* Harvey P. Dale, May 21 2023 *)

A021108 Decimal expansion of 1/104.

Original entry on oeis.org

0, 0, 9, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4, 6, 1, 5, 3, 8, 4

Offset: 0

N. J. A. Sloane

After 9, periodic with period 6: [6, 1, 5, 3, 8, 4]. See also A021030 (1/26), A021069 (1/65), A021420 (1/416), A021654 (1/650). - Bruno Berselli, Apr 13 2018

			0.009615384615384615384615384615384615384615384615384615384615384...

Index entries for linear recurrences with constant coefficients, signature (1,0,-1,1).

Join[{0, 0}, RealDigits[1/104, 10, 120][[1]]] (* or *) PadRight[{0, 0, 9, 6}, 120,{3, 8, 4, 6, 1, 5}] (* Harvey P. Dale, Aug 18 2012 *)

Equals A020821 * A021017 = A020773 * A021030 = A020761 * A021056. - Bruno Berselli, Apr 13 2018

A021199 Decimal expansion of 1/195.

Original entry on oeis.org

0, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5, 1, 2, 8, 2, 0, 5

Offset: 0

N. J. A. Sloane

Without the initial zeros, decimal expansion of 20/39. Period is of length 6: 5, 1, 2, 8, 2, 0. - Alonso del Arte, May 26 2018

			0.0051282051282051282051282051282051282...

Index entries for linear recurrences with constant coefficients, signature (1, -1, 1, -1, 1).

Cf. A021069 (1/65).

Join[{0, 0}, RealDigits[1/195, 10, 104][[1]]] (* Alonso del Arte, May 13 2018 *)

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A351474 Numbers m such that the largest digit in the decimal expansion of 1/m is 8.

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A021654 Decimal expansion of 1/650.

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A021108 Decimal expansion of 1/104.

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A021199 Decimal expansion of 1/195.

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