login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A309320 a(n) is the smallest positive integer m such that the digits of n in base 10 are also the first digits of sin(m) in base 10 after the decimal point. 1
0, 3, 6, 53, 9, 10, 7, 4, 1, 2, 91, 69, 47, 25, 3, 41, 63, 85, 107, 129, 151, 160, 138, 116, 94, 72, 50, 6, 16, 38, 60, 82, 104, 148, 170, 163, 141, 97, 75, 53, 31, 9, 13, 57, 79, 101, 145, 167, 166, 122, 100, 78, 34, 12, 10, 32, 76, 98, 120, 164, 147, 125, 81 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

James Carruthers, Table of n, a(n) for n = 0..10000

EXAMPLE

a(1) = 3 because we have sin(1.) = 0.8414709848..., sin(2.) = 0.9092974268..., sin(3.) = 0.1411200081.. - N. J. A. Sloane, Sep 28 2019

MATHEMATICA

a[0] =0; a[n_] := Module[{m = 1}, While[(d = IntegerDigits[n]) != RealDigits[ Sin[m], 10, Length[d], -1][[1]], m++]; m]; Array[a, 100, 0] (* Amiram Eldar, Sep 28 2019 *)

PROG

(Python) import numpy as np

import math as m

n = 1

i = 0

inp = np.zeros(1)

out = inp

while n < 10001:

    k=m.fabs( m.trunc( m.sin(i) * m.pow( 10, m.floor( m.log10(n)+1 ) ) ) )

    if k==n:

        inp = np.append(inp, int(n))

        out = np.append(out, int(i))

        print(n, i)

        n += 1

        i = 0

        continue

    else:

        i+=1

CROSSREFS

Sequence in context: A102931 A056447 A056437 * A012275 A067608 A023177

Adjacent sequences:  A309317 A309318 A309319 * A309321 A309322 A309323

KEYWORD

nonn,base,easy

AUTHOR

James Carruthers, Sep 21 2019

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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 24 23:16 EDT 2021. Contains 345445 sequences. (Running on oeis4.)