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!)
A089377 Numbers whose product of digits +1 and -1 gives twin prime pairs. 2
4, 6, 14, 16, 22, 23, 26, 29, 32, 34, 36, 41, 43, 56, 61, 62, 63, 65, 67, 76, 89, 92, 98, 114, 116, 122, 123, 126, 129, 132, 134, 136, 141, 143, 156, 161, 162, 163, 165, 167, 176, 189, 192, 198, 212, 213, 216, 219, 221, 223, 231, 232, 233, 235, 237, 249, 253, 256 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
36 is a member since 3*6 = 18 and (17,19) is a twin prime pair.
MATHEMATICA
prodDig[n_] := Times @@ IntegerDigits[n]; Select[Range[256], And @@ PrimeQ [prodDig[#] + {-1, 1}] &] (* Amiram Eldar, Dec 27 2019 *)
Select[Range[300], AllTrue[Times@@IntegerDigits[#]+{1, -1}, PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 26 2021 *)
CROSSREFS
Sequence in context: A310619 A343501 A029641 * A310620 A310621 A090773
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Nov 08 2003
EXTENSIONS
More terms from David Wasserman, Sep 15 2005
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 June 20 23:53 EDT 2024. Contains 373535 sequences. (Running on oeis4.)