OFFSET
0,1
COMMENTS
There may be other numbers with this property.
REFERENCES
W. Sierpiński, 250 Problems in Elementary Number Theory, American Elsevier Publ. Comp., New York, PWN-Polish Scientific Publishers, Warszawa, 1970, Problem 227, p. 20 and p. 110.
LINKS
FORMULA
a(n) = A259058(n)/2.
a(n) = 2*n^2 + 36*n + 227.
O.g.f.: (227 - 416*x + 193*x^2)/(1-x)^3.
a(n) = 3*a(n-1)-3*a(n-2)+a(n-3). - Vincenzo Librandi, Aug 13 2015
MAPLE
MATHEMATICA
CoefficientList[Series[(227 - 416 x + 193 x^2)/(1 - x)^3, {x, 0, 50}], x] (* Vincenzo Librandi, Aug 13 2015 *)
PROG
(Magma) [2*n^2+36*n+227: n in [0..50]] /* or */ I:=[227, 265, 307]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+Self(n-3): n in [1..50]]; // Vincenzo Librandi, Aug 13 2015
(PARI) a(n)=2*n^2+36*n+227 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Aug 12 2015
STATUS
approved