OFFSET
1,1
COMMENTS
Luhn primes were named after Norman Luhn, who first noted the property of 229 on the website Prime Curios!.
There are no Luhn primes in odd base, and only one, 2, in base 2.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
Octavian Cira and Florentin Smarandache, Luhn prime numbers, Theory and Applications of Mathematics & Computer Science, Vol. 5, No. 1 (2015), pp. 1-8.
G. L. Honaker, Jr. and Chris Caldwell, eds., 229, Prime Curios!, November 19, 2001.
FORMULA
a(n) > 8*n^2 for n > 1.
EXAMPLE
a(2) = 37 since 37 = 211 in base 2*2 = 4, and 211+112 = 323 which equals 59 in base 10 and is prime.
MATHEMATICA
a[b_] := Module[{p=2}, While[!PrimeQ[p + FromDigits[Reverse @ IntegerDigits[p, b], b]], p = NextPrime[p]]; p]; Table[a[n], {n, 2, 88, 2}]
PROG
(PARI) a(n) = {my(p=2); while (!isprime(p+fromdigits(Vecrev(digits(p, 2*n)), 2*n)), p = nextprime(p+1)); p; } \\ Michel Marcus, Aug 03 2019
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Amiram Eldar, Aug 02 2019
STATUS
approved