OFFSET
1,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
a(11) = 4 because there are 4 divisors of 11th positive palindromic number (i.e., 22).
MATHEMATICA
palQ[n_]:=Module[{idn=IntegerDigits[n]}, idn==Reverse[idn]]; DivisorSigma[ 0, #]&/@ Select[Range[1000], palQ] (* Harvey P. Dale, Nov 29 2014 *)
PROG
(Python)
from sympy import divisor_count
def A076888(n):
y = 10*(x:=10**(len(str(n+1>>1))-1))
return divisor_count(int((c:=n+1-x)*x+int(str(c)[-2::-1] or 0) if n+1<x+y else (c:=n+1-y)*y+int(str(c)[::-1] or 0))) # Chai Wah Wu, Jul 24 2024
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Shyam Sunder Gupta, Nov 25 2002
STATUS
approved