OFFSET
1,1
COMMENTS
There are 133 terms below 2^64. Only 4 of them are also Carmichael numbers (561, 1105, 278545 and 67371265).
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..133
EXAMPLE
341 is a term since 341 = 101010101_2 is palindromic in base 2, it is composite (= 11 * 31) and 2^340 == 1 (mod 341).
MATHEMATICA
pspQ[n_] := CompositeQ[n] && PowerMod[2, n-1, n] == 1; Select[Range[10^6], PalindromeQ[IntegerDigits[#, 2]] && pspQ[#] &]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Amiram Eldar, Jul 23 2021
STATUS
approved