A117056 Palindromes for which both the sum of the digits and the product of the digits are also palindromes.
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 101, 111, 121, 131, 141, 151, 161, 171, 191, 202, 212, 222, 303, 313, 404, 1001, 1111, 1221, 1331, 2002, 2112, 3003, 3113, 4004, 10001, 10101, 10201, 10301, 10401, 10501, 10601, 10701, 10901, 11011, 11111, 11211
Offset: 1
Examples
11711 is in the sequence because (1) it is a palindrome, (2)the sum of its digits 1+1+7+1+1=11 is a palindrome and (3)the product of its digits 1*1*7*1*1=7 is also a palindrome.
Links
- Chai Wah Wu, Table of n, a(n) for n = 1..10000
Crossrefs
Cf. A002113.
Programs
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Mathematica
id[n_]:=IntegerDigits[n]; palQ[n_]:=Reverse[x=id[n]]==x; t={}; Do[If[palQ[n] && palQ[Plus@@id[n]] && palQ[Times@@id[n]],AppendTo[t,n]],{n,0,11220}]; t (* Jayanta Basu, May 15 2013 *) Select[Range[0,12000],AllTrue[{#,Total[IntegerDigits[#]],Times@@IntegerDigits[#]},PalindromeQ]&] (* Harvey P. Dale, Jul 05 2022 *)
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PARI
ispal(n)=n=digits(n);for(i=1,#n\2,if(n[i]!=n[#n+1-i],return(0)));1 is(n)=my(d=vecsort(digits(n)));ispal(sum(i=1,#d,d[i]))&&ispal(prod(i=1,#d,d[i]))&&ispal(n) \\ Charles R Greathouse IV, May 15 2013