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A125832 Numbers n which have exactly 14 representations as a product of two palindromes. 2
5426124, 8139186, 20017998, 21999978, 26690664, 26888862, 29333304, 49821684, 73267326, 97689768, 98666568, 146534652, 147999852, 220197978, 271333062, 274019262, 320221902, 403696293, 471535064, 489372884, 516019504, 518221704 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

26888862 is in the sequence since 26888862 = 1*26888862 = 2*13444431

= 11*2444442 = 22*1222221 = 111*242242 = 121*222222 = 222*121121

= 242*111111 = 1001*26862 = 1221*22022 = 1331*20202 = 2002*13431

= 2442*11011 = 2662*10101.

MATHEMATICA

f[n_]:=f[n]=Length[Select[Divisors[n], #<=n^(1/2)&&FromDigits[ Reverse[IntegerDigits[ # ]]]==#&&FromDigits[Reverse[IntegerDigits [n/# ]]]==n/#&]]; Do[If[f[n]==14, Print[n]], {n, 50000000}]

CROSSREFS

Cf. A116993, A125833, A125834.

Sequence in context: A092020 A029822 A263214 * A206325 A203549 A230793

Adjacent sequences:  A125829 A125830 A125831 * A125833 A125834 A125835

KEYWORD

base,nonn

AUTHOR

Farideh Firoozbakht, Dec 10 2006

EXTENSIONS

a(9)-a(22) from Donovan Johnson, Aug 05 2009

STATUS

approved

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Last modified November 18 19:59 EST 2019. Contains 329288 sequences. (Running on oeis4.)