OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = n^3+n+1.
G.f.: (1 - x + 5*x^2 + x^3)/(1 - x)^4. - Philippe Deléham, Jun 06 2015
a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4). - Wesley Ivan Hurt, May 04 2021
MATHEMATICA
sk[n_]:=Module[{k=n+1, n2=n^2, n3=n^3+1}, While[!Divisible[k*n2+1, n3], k++]; k]; Array[sk, 40] (* Harvey P. Dale, Jun 13 2013 *)
PROG
(PARI) for(n=1, 50, s=n+1; while((s*n^2+1)%(n^3+1)>0, s++); print1(s, ", "))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, May 31 2002
EXTENSIONS
a(0) from Philippe Deléham, Jun 06 2015
STATUS
approved