A232893 Numbers whose sum of square divisors is a palindrome in base 10 having at least two digits.

15376, 30752, 46128, 76880, 92256, 107632, 153760, 169136, 199888, 215264, 230640, 261392, 292144, 322896, 338272, 353648, 399776, 445904, 461280, 476656, 507408, 522784, 538160, 568912, 584288, 599664, 630416, 645792, 661168, 707296, 722672, 784176, 814928, 845680, 876432

Offset

1,1

Links

Table of n, a(n) for n=1..35.

Example

Sum of square divisor of 15376, 15376+3844+961+16+4+1=20202, a palindrome with five digits.

Mathematica

ssdpQ[n_]:=Module[{s=Total[Select[Divisors[n], IntegerQ[Sqrt[#]]&]]}, IntegerLength[ s]>1 &&s==IntegerReverse[s]]; Select[Range[ 900000], ssdpQ] (* The program uses the IntegerReverse function from Mathematica version 10 *) (* Harvey P. Dale, Jan 31 2016 *)

Prog

(PARI)
reverse(n)=concat(Vecrev(Str(n)))
palind(n)=(Str(n)==reverse(n)&&n>10)
{for(n=1, 10^6, k=sumdiv(n, d, d*issquare(d)); if(palind(k), print(n)))}

Crossrefs

Cf. A232892.

Sequence in context: A232382 A175751 A054834 * A054835 A182255 A054836

Adjacent sequences: A232890 A232891 A232892 * A232894 A232895 A232896

Keyword

nonn,base

Author

Antonio Roldán, Dec 02 2013

Status

approved