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!)
A271361 Numbers n such that 63*10^n+1 is prime. 0
1, 2, 12, 21, 27, 30, 33, 44, 46, 76, 78, 83, 84, 92, 582, 750, 787, 3218, 3290, 5617, 6385, 13960, 22705, 27636, 36497, 50349, 51169, 70381, 70486, 73096 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers such that the digits 63 followed by n-1 occurrences of the digit 0 followed by the digit 1 is prime (see Example section).

a(31) > 10^5.

LINKS

Table of n, a(n) for n=1..30.

Makoto Kamada, Search for 630w1.

EXAMPLE

2 is in this sequence because 63*10^2+1 = 6301 is prime.

Initial terms and primes associated:

a(1) = 1, 631;

a(2) = 2, 6301;

a(3) = 12, 63000000000001;

a(4) = 21, 63000000000000000000001;

a(5) = 27, 63000000000000000000000000001, etc.

MATHEMATICA

Select[Range[0, 100000], PrimeQ[63*10^#+1] &]

PROG

(PARI) is(n)=ispseudoprime(63*10^n+1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269.

Sequence in context: A031001 A048955 A034049 * A304813 A279424 A073041

Adjacent sequences:  A271358 A271359 A271360 * A271362 A271363 A271364

KEYWORD

nonn,more

AUTHOR

Robert Price, Apr 05 2016

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 15 08:52 EDT 2021. Contains 345048 sequences. (Running on oeis4.)