OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,0,0,0,0,0,1,-1).
FORMULA
From Chai Wah Wu, Nov 14 2024: (Start)
a(n) = a(n-1) + a(n-12) - a(n-13) for n > 13.
G.f.: x*(4*x^12 + 6*x^11 + 6*x^10 + 5*x^9 + 4*x^8 + 4*x^7 + 5*x^6 + 5*x^5 + 6*x^4 + 4*x^3 + 4*x^2 + 5*x + 2)/(x^13 - x^12 - x + 1). (End)
MATHEMATICA
NestList[Complement[Range[3+#], Divisors[#]][[3]]+#&, 2, 60] (* Harvey P. Dale, Jan 15 2024 *)
PROG
(PARI) third(n) = {my(nb = 0, k = 1); while (nb != 3, if (n % k, nb++); if (nb != 3, k++); ); k; }
f(n) = n + third(n);
lista2(nn) = {a = 2; print1(a, ", "); for (n=2, nn, newa = f(a); print1(newa, ", "); a = f(a); ); } \\ Michel Marcus, Oct 04 2018
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Jacques Tramu, Jun 25 2008
EXTENSIONS
More terms from Michel Marcus, Oct 04 2018
STATUS
approved