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!)
A020206 Pseudoprimes to base 78. 1
77, 341, 385, 451, 553, 703, 869, 1045, 1247, 1271, 1441, 1849, 1921, 2047, 2465, 2765, 3097, 4061, 4187, 4345, 4577, 5371, 6031, 6083, 6085, 6545, 6601, 8321, 8911, 8965, 10585, 13333, 13981, 15211, 15251, 15841, 17711, 17767, 20689, 22801, 23281, 23617 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Composite numbers n such that 78^(n-1) == 1 (mod n). - Michel Lagneau, Feb 18 2012

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

Index entries for sequences related to pseudoprimes

MATHEMATICA

base = 78; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n-1, n] == 1, AppendTo[t, n]]]; t (* T. D. Noe, Feb 21 2012 *)

Select[Range[25000], CompositeQ[#]&&PowerMod[78, #-1, #]==1&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 11 2019 *)

CROSSREFS

Cf. A001567 (pseudoprimes to base 2).

Sequence in context: A158767 A158771 A331976 * A020304 A154058 A027574

Adjacent sequences:  A020203 A020204 A020205 * A020207 A020208 A020209

KEYWORD

nonn

AUTHOR

David W. Wilson

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 1 07:40 EDT 2020. Contains 334759 sequences. (Running on oeis4.)