Search: id:A090315
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%I A090315
%S A090315 1,2,4,6,14641,44,0,24,484,272,0,294,0,291008,44944,264,0,252,0,2992,0,
%T A090315 2532352,0,2508,10004000600040001,2977792,1002001,2112,0,63536,0,4224,
               0,
%U A090315 44356665344,0,2772,0,2380651036672,0,42224,0,6336,0,2937856,698896,0
%N A090315 Least k such that k and digit reversal of k both have n divisors, or 
               0 if no such number exist.
%C A090315 For a(7) one needs a number of the form p^6 whose digit reversal is q^6, 
               p, q are primes. Hence a(7) perhaps is zero (not sure). Conjecture: 
               There are infinitely many nonzero terms as well as zeros in this 
               sequence.
%C A090315 Zeros are unproved. I have checked for a(21) up to 10^13, a(46) up to 
               10^14, a(33) up to 10^18, a(39) up to 10^20, a(35) up to 10^30 and 
               the rest (7, 11, 13, 17, 19, 23, 29, 31, 37, 41 and 43) up to at 
               least 10^48. - David Wasserman (wasserma(AT)spawar.navy.mil), Nov 
               01 2005
%e A090315 a(8) =24, tau(24) = tau(42) = 8.
%Y A090315 Cf. A083753.
%Y A090315 Sequence in context: A056012 A066719 A033319 this_sequence A083753 A111512 
               A111768
%Y A090315 Adjacent sequences: A090312 A090313 A090314 this_sequence A090316 A090317 
               A090318
%K A090315 base,nonn
%O A090315 1,2
%A A090315 Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Dec 01 2003
%E A090315 More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Nov 01 
               2005

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