A378140 a(n) is the least palindrome that has exactly n palindromic divisors other than itself and 1.
1, 4, 6, 232, 44, 636, 66, 484, 888, 616, 2442, 2112, 4224, 6006, 2772, 26862, 23232, 232232, 46464, 297792, 66066, 88088, 222222, 252252, 213312, 21122112, 234432, 606606, 828828, 444444, 279972, 21211212, 666666, 2444442, 2114112, 2578752, 888888, 4228224, 42422424, 23555532, 54999945, 82711728
Offset: 0
Examples
a(4) = 44 because 44 is a palindrome with exactly 4 palindromic divisors other than itself and 1, namely 2, 4, 11 and 22, and no smaller palindrome works.
Programs
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Maple
ispali:= proc(n) rev(n) = n end proc: g:= proc(x) nops(select(ispali,numtheory:-divisors(x) minus {1,x})) end proc: F:= proc(m) local x1,x2,x3; if m::even then [seq(seq(rev(x1) + 10^(m/2)*x1, x1 = 10^(m/2-1) .. 10^(m/2)-1))] else [seq(seq(rev(x1) + 10^((m-1)/2)*x2 + 10^((m+1)/2)*x1,x2=0..9),x1=10^((m-1)/2-1)..10^((m-1)/2)-1)]; fi end proc: N:= 50: # for a(0) .. a(N) V:= Array(0..N): count:= 0: for d from 1 while count
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