This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A112981 #8 Jan 25 2018 15:16:30
%S A112981 1,1,1,3,29,24417,14557168544129,
%T A112981 3084826414596074361107793217201624802791
%N A112981 a(1) = a(2) = a(3) = 1; for n>3: a(n) = a(n-1)^3 + a(n-2)^3 + a(n-3)^3.
%C A112981 A cubic tribonacci sequence.
%C A112981 This is a cubic analog of a tribonacci sequence A000213, similarly to A000283 being the quadratic analog of the Fibonacci sequence A000045. a(4) and a(5) are primes; a(7) is semiprime; a(6) and a(8) have 3 prime factors. a(9) has 119 digits.
%e A112981 a(6) = 1^3 + 3^3 + 29^3 = 24417.
%t A112981 RecurrenceTable[{a[1]==a[2]==a[3]==1,a[n]==a[n-1]^3+a[n-2]^3+a[n-3]^3},a,{n,10}] (* _Harvey P. Dale_, Jan 25 2018 *)
%Y A112981 Cf. A000045, A000213, A000283.
%K A112981 easy,nonn
%O A112981 1,4
%A A112981 _Jonathan Vos Post_, Jan 02 2006