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 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. 0
 1, 1, 1, 3, 29, 24417, 14557168544129, 3084826414596074361107793217201624802791 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS A cubic tribonacci sequence. 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. LINKS EXAMPLE a(6) = 1^3 + 3^3 + 29^3 = 24417. MATHEMATICA RecurrenceTable[{a==a==a==1, a[n]==a[n-1]^3+a[n-2]^3+a[n-3]^3}, a, {n, 10}] (* Harvey P. Dale, Jan 25 2018 *) CROSSREFS Cf. A000045, A000213, A000283. Sequence in context: A139517 A156026 A171883 * A178336 A176495 A318971 Adjacent sequences:  A112978 A112979 A112980 * A112982 A112983 A112984 KEYWORD easy,nonn AUTHOR Jonathan Vos Post, Jan 02 2006 STATUS approved

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Last modified April 19 08:26 EDT 2021. Contains 343110 sequences. (Running on oeis4.)