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%I #9 Sep 18 2015 04:13:51
%S 9,49,403,91567,15710338,22299240301,410215255975,
%T 16028490260973271564,3675428737957071376458418697257441432,
%U 68870283995769119153444423083582483731047501259451576,117132053040627211700855551462169332419627937481594387132326105147,123777964225587033644972609912682600644825032245501533642224841942296666013617
%N Product of n-th Mersenne prime and n-th Mersenne prime written backwards.
%H Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>.
%F a(n) = A000668(n)*A135623(n).
%e a(3) = 403 because the 3rd Mersenne prime is 31 and 31*13 = 403.
%p read transforms : A000043 := proc(n) op(n,[2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203, 2281, 3217, 4253, 4423, 9689, 9941, 11213, 19937]) ; end: A000668 := proc(n) 2^A000043(n)-1 ; end: A135623 := proc(n) digrev(A000668(n)) ; end: A135625 := proc(n) A000668(n)*A135623(n) ; end: for n from 1 to 13 do printf("%d, ",A135625 (n) ) ; od: # _R. J. Mathar_, Feb 28 2008
%t # FromDigits[Reverse[IntegerDigits[#]]]&/@Select[2^Prime[Range[100]]-1, PrimeQ] (* _Harvey P. Dale_, Mar 26 2012 *)
%Y Cf. A000668, A133019, A135623.
%K base,nonn
%O 1,1
%A _Omar E. Pol_, Feb 20 2008
%E More terms from _R. J. Mathar_, Feb 28 2008
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