OFFSET
1,2
COMMENTS
1/a(n), for n >= 2, is in base n represented by 0.repeat(0,0,0,1,1,1). This is instance p = 3 of the general formula for 0.repeat(0^(q),1^(q)) (meaning here q zeros followed by q 1's) in base b >= 2 which is 1/a(q,b) with a(q,b) = (b - 1)*(b^p + 1), for p >= 1.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
FORMULA
a(n) = (n - 1)*(n^3 + 1) = n^4 - n^3 + n - 1, n >= 1.
O.g.f.: x^2*(9 + 11*x + 5*x^2 - x^3)/(1 - x)^5.
MAPLE
MATHEMATICA
Table[n^4-n^3+n-1, {n, 40}] (* Harvey P. Dale, Jun 20 2019 *)
PROG
(Magma) [(n - 1)*(n^3 + 1) : n in [1..50]]; // Wesley Ivan Hurt, Jun 20 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Jun 20 2014
STATUS
approved