|
|
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
a(11) = A038396(42) + 1 = 84...43, a(12) = A038396(54) + 1 = 108...43;
a(13) = A038396(185) + 1 = 370...43, a(14) = A038396(199) - 1 = 398...41;
a(15) = A038396(224) + 1 = 448...43, a(16) = A038396(248) - 1 = 496...41;
a(17) = A038396(346) - 1 = 692...41, a(18) = A038396(947) - 1 = 1894...41.
a(19) (if it exists) will be more than A038396(3000).
a(2) and a(3) are a pair of twin primes, a(4) and a(5) also.
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[#, PrimeQ] &@ Flatten@ Table[{# - 1, # + 1} &@ FromDigits@ Flatten@ Reverse@ Take[#, n], {n, Length@ #}] &@ Array[IntegerDigits[2 #] &, 40] (* Michael De Vlieger, May 14 2017 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|