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A232892 Numbers whose sum of proper square divisors is a palindrome in base 10 having at least two digits. 1
144, 324, 1089, 1936, 5929, 13225, 30752, 46128, 58564, 76880, 92256, 107632, 125316, 138384, 149769, 153760, 154449, 169136, 199888, 215264, 230640, 261392, 292144, 322896, 338272, 342225, 353648, 378225, 399776, 405769, 445904, 461280, 476656, 507408, 522784, 538160, 568912 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..37.

EXAMPLE

Sum of proper square divisors of 324: 81+36+9+4+1=131, is a palindrome with three digits.

MATHEMATICA

pb10Q[n_]:=Module[{t=Total[Select[Most[Divisors[n]], IntegerQ[ Sqrt[ #]]&]]}, IntegerLength[ t]>1&&PalindromeQ[t]]; Select[Range[ 600000], pb10Q] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 01 2017 *)

PROG

(PARI)

reverse(n)=concat(Vecrev(Str(n)))

palind(n)=(Str(n)==reverse(n)&&n>10)

{for(n=1, 6*10^5, k=sumdiv(n, d, d*issquare(d)*(d<n)); if(palind(k), print(n)))}

CROSSREFS

Cf. A232893.

Sequence in context: A217584 A030633 A189988 * A034285 A211469 A248551

Adjacent sequences:  A232889 A232890 A232891 * A232893 A232894 A232895

KEYWORD

nonn,base

AUTHOR

Antonio Roldán, Dec 02 2013

STATUS

approved

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Last modified January 21 13:52 EST 2018. Contains 297994 sequences.