login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A212601 Intersection of A001567 and A212502. 2
4033, 6601, 8321, 15841, 25761, 29341, 41041, 46657, 75361, 115921, 162401, 172081, 252601, 294409, 314821, 332949, 401401, 410041, 488881, 530881, 552721, 642001, 721801, 873181, 934021, 1004653, 1207361, 1461241, 1876393, 1909001, 2081713, 2085301, 2113921 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Only 1 (mod 4) numbers have been found.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

MATHEMATICA

t[n_] := Which[Mod[n, 4] == 3, n + 1, Mod[n, 4] == 1, n - 1,  True,  n]; Select[1 + Range[99000], PowerMod[2, # - 1, #] == 1 && !PrimeQ[#] && Im[PowerMod[1 + 2I, t[#], #]] == 0 &]

CROSSREFS

Cf. A201629.

Cf. A001567 (pseudoprimes to base 2).

Cf. A212502 (pseudoprimes to base 1+2i).

Sequence in context: A329881 A234838 A234834 * A060896 A206617 A252686

Adjacent sequences:  A212598 A212599 A212600 * A212602 A212603 A212604

KEYWORD

nonn

AUTHOR

José María Grau Ribas, May 22 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 13 22:39 EDT 2022. Contains 356109 sequences. (Running on oeis4.)