OFFSET
1,2
COMMENTS
The sequence starts with a(1) = 1 and is always extended with the smallest integer not yet present that does not lead to a contradiction. This sequence is conjectured to be a permutation of the odd integers not ending with the digit “5”.
A variant of A275602
LINKS
Jean-Marc Falcoz, Table of n, a(n) for n = 1..7856
EXAMPLE
|1-3| = 2 and 23 is prime; |3-7| = 4 and 47 is prime; |7-9| = 2 and 29 is prime; |9-11| = 2 and 211 is prime; |11-17| = 6 and 617 is prime; etc.
MATHEMATICA
a = {1}; Do[k = 1; While[Or[! PrimeQ@ FromDigits[IntegerDigits[Abs[a[[i - 1]] - k]]~Join~IntegerDigits[k]], MemberQ[a, k]], k++]; AppendTo[a, k], {i, 2, 71}]; a (* Michael De Vlieger, Nov 14 2016 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Eric Angelini and Jean-Marc Falcoz, Nov 14 2016
STATUS
approved