%I A113153
%S A113153 1,2,4,8,17,54,472,27216,84738887,299164114847940,
%T A113153 311903053042108587337426568,
%U A113153 5846720173185251353387753850814872871131756204168
%N A113153 Sum of the first n tribonacci numbers, in ascending order, as bases, 
               with the same, in descending order, as exponents.
%F A113153 a(n) = SUM[from i = 1 to n] (A000073(i))^A000073(n-i+1)
%e A113153 For the tribonacci sequence, starting t(1)=t(2)=1:
%e A113153 a(1) = t(1)^t(1) = 1^1 = 1.
%e A113153 a(2) = t(1)^t(2) + t(2)^t(1) = 1^1 + 1^1 = 2.
%e A113153 a(3) = t(1)^t(3) + t(2)^t(2) + t(3)^t(1) = 1^2 + 1^1 + 2^1 = 4.
%e A113153 a(4) = t(1)^t(4) + t(2)^t(3) + t(3)^t(2) + t(4)^t(1) = 1^4 + 1^2 + 2^1 
               + 4^1 = 8.
%e A113153 a(5) = 1^7 + 1^4 + 2^2 + 4^1 + 7^1 = 17.
%e A113153 a(6) = 1^13 + 1^7 + 2^4 + 4^2 + 7^1 + 13^1 = 54.
%e A113153 a(7) = 1^24 + 1^13 + 2^7 + 4^4 + 7^2 + 13^1 + 24^1 = 472.
%e A113153 a(8) = 1^44 + 1^24 + 2^13 + 4^7 + 7^4 + 13^2 + 24^1 + 44^1 = 27216.
%e A113153 a(9) = 1^81 + 1^44 + 2^24 + 4^13 + 7^7 + 13^4 + 24^2 + 44^1 + 81^1 = 
               84738887.
%e A113153 a(10) = 1^149 + 1^81 + 2^44 + 4^24 + 7^13 + 13^7 + 24^4 + 44^2 + 81^1 
               + 149^1 = 299164114847940.
%e A113153 a(11) = 1^274 + 1^149 + 2^81 + 4^44 + 7^24 + 13^13 + 24^7 + 44^4 + 81^2 
               + 149^1 + 274^1 = 311903053042108587337426568.
%e A113153 a(12) = 1^504 + 1^274 + 2^149 + 4^81 + 7^44 + 13^24 + 24^13 + 44^7 + 
               81^4 + 149^2 + 274^1 + 504^1 = 5846720173185251353387753850814872871131756204168.
%Y A113153 Cf. A000073.
%Y A113153 Sequence in context: A090375 A104879 A156805 this_sequence A092507 A024415 
               A018096
%Y A113153 Adjacent sequences: A113150 A113151 A113152 this_sequence A113154 A113155 
               A113156
%K A113153 easy,nonn
%O A113153 1,2
%A A113153 Jonathan Vos Post (jvospost3(AT)gmail.com), Jan 04 2006