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A334822 Palindromes k such that k*sod(k) and k/sod(k) are both palindromes, where sod(k) denotes the sum of digits of k (A007953). 1

%I #14 May 16 2020 01:45:44

%S 1,2,3,144689999986441,154698898896451,226589999985622,

%T 234779999977432,243788999887342,244788898887442,253698898896352,

%U 254689878986452,254788878887452,254797797797452,333878999878333,334878898878433,335598898895533,336589878985633,336688878886633

%N Palindromes k such that k*sod(k) and k/sod(k) are both palindromes, where sod(k) denotes the sum of digits of k (A007953).

%C Intersection of A002113 and A229549 and A334416. Palindromes in A334533.

%C For the first 10000 terms, most of them have digit sum 91. The only terms a(n) for n <= 10000 for which the digit sum is not 91 are 1, 2, 3 and a(1076) = 426666666666666624. - _Chai Wah Wu_, May 15 2020

%H Chai Wah Wu, <a href="/A334822/b334822.txt">Table of n, a(n) for n = 1..10000</a>

%e 35479654545697453 is a palindrome whose sum of digits is 91. 35479654545697453/91 = 389886313688983 and 35479654545697453*91 = 3228648563658468223 which are both palindromes. So 35479654545697453 is a term.

%Y Cf. A002113, A007953, A229549, A334416, A334533.

%K nonn,base

%O 1,2

%A _Chai Wah Wu_, May 12 2020

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