A117785 Total number of palindromic primes in base 8 below 8^n.
4, 4, 17, 17, 64, 64, 375, 375, 2319, 2319, 15130, 15130, 99554, 99554, 675166, 675166, 4753617, 4753617, 33752394, 33752394, 239605153, 239605153
Offset: 1
Links
- Eric Weisstein: Palindromic Prime.
Programs
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Maple
revdigs:= proc(n) local L,i; L:= convert(n,base,8); add(L[-i]*8^(i-1),i=1..nops(L)) end proc: f:= proc(d) local x,y; nops(select(isprime, [seq(seq(x*8^(d+1)+y*8^d+revdigs(x), y=0..7),x=8^(d-1)..8^d-1)])); end proc: T:= ListTools:-PartialSums([4, op(map(f,[$1..6]))]): map(t -> (t,t), T); # Robert Israel, Aug 01 2019
Extensions
a(9)-a(22) from Robert Israel, Aug 01 2019, using data from A117786.
Comments