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A171741 The first 3-fold intrinsically n-palindromic number (given in base ten). 24
18, 154, 19040, 267140, 2853326516320, 3360633 (list; graph; refs; listen; history; text; internal format)



The large value for the 6-palindrome case, a(6)=2853326516320, has 139 as the smallest of the three bases.

Coincidentally, the following much shorter term, a(7)= 3360633, involves base 9 through 11, the conjunction of base-9 and base-10 palindromes (A029965) comes up a term short (assuming space limitations remain as they are at the beginning of 2011), and A053740 is a totally unrelated collection of palindromes that also contains 33633.

a(8) > 10^18. - Hiroaki Yamanouchi, Aug 22 2015


Table of n, a(n) for n=2..7.


a(5)=267140 is 6D4D6 in base 14, 54245 in base 15, and 29E92 in base 18.

a(7)=3360633 is 6281826 in base 9 and 1995991 in base 11.


Cf. A171701, A171702, A171703, A171704, A171705, A171706, A171740, A171742, A053780, A029966, A029965.

Sequence in context: A022613 A060221 A244876 * A197239 A060932 A300078

Adjacent sequences:  A171738 A171739 A171740 * A171742 A171743 A171744




James G. Merickel, Dec 17 2009



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Last modified December 11 18:49 EST 2019. Contains 329925 sequences. (Running on oeis4.)