cp's OEIS Frontend

A322924 Sum of n-th Bell number and n-th Bell number written backwards.

%I A322924 #14 Sep 08 2022 08:46:23
%S A322924 2,2,4,10,66,77,505,1655,4554,95259,695486,754446,12166721,101089109,
%T A322924 414897413,6841551376,84604250548,123761716632,1633685476445,
%U A322924 13337764677442,79077443378087,632521435125225,7744164113623377,108500061705109490,1428467362263664833
%N A322924 Sum of n-th Bell number and n-th Bell number written backwards.
%C A322924 After 2, the next prime Bell number is a(110), which has 131 digits.
%H A322924 Robert Israel, <a href="/A322924/b322924.txt">Table of n, a(n) for n = 0..500</a>
%F A322924 a(n) = A000110(n) + A004098(n).
%e A322924 a(4) = 66 because Bell(4) = 15 and 15 + 51 = 66.
%e A322924 a(5) = 77 because Bell(5) = 52 and 52 + 25 = 77.
%p A322924 g:= proc(n) local L,i;
%p A322924 L:= convert(n,base,10);
%p A322924 n + add(L[-i]*10^(i-1),i=1..nops(L))
%p A322924 end proc:
%p A322924 map(g @ combinat:-bell, [$0..30]); # _Robert Israel_, Mar 13 2019
%t A322924 BellB[#] + FromDigits[Reverse[IntegerDigits[BellB[#]]]]&/@Range[0, 30]
%o A322924 (Magma) [Bell(n) + Seqint(Reverse(Intseq(Bell(n)))): n in [0..30]];
%Y A322924 Cf. A000110, A004098, A051131, A302092.
%K A322924 nonn,base,easy
%O A322924 0,1
%A A322924 _Vincenzo Librandi_, Mar 12 2019