cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A117056 Palindromes for which both the sum of the digits and the product of the digits are also palindromes.

Original entry on oeis.org

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

Views

Author

Luc Stevens (lms022(AT)yahoo.com), Apr 16 2006

Keywords

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.
		

Crossrefs

Cf. A002113.

Programs

  • 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 *)
  • 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