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!)
A032618 Numbers n such that n concatenated with n + 3 is a prime. 2
4, 8, 10, 16, 44, 46, 56, 58, 68, 74, 86, 94, 98, 100, 104, 106, 136, 140, 148, 154, 158, 160, 166, 176, 184, 194, 206, 230, 244, 250, 254, 260, 266, 268, 274, 286, 296, 308, 310, 328, 338, 344, 346, 370, 380, 388, 410, 416, 430, 434, 436, 440, 448, 460 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

filter:= n -> isprime(n*(10^(1+ilog10(n+3))+1)+3):

select(filter, [seq(i, i=4..1000, 2)]); # Robert Israel, Nov 14 2019

MATHEMATICA

Select[Range[500], PrimeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ #+3]]]]&] (* Harvey P. Dale, Jul 19 2011 *)

CROSSREFS

Cf. A032608.

Sequence in context: A311007 A232168 A046559 * A311008 A311009 A311010

Adjacent sequences:  A032615 A032616 A032617 * A032619 A032620 A032621

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, May 15 1998

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 May 27 13:00 EDT 2020. Contains 334657 sequences. (Running on oeis4.)