A180486 Numbers of the form ceiling(A179896(j)/A018252(j)) where A179896(j) mod A018252(j) <> 0.

5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47, 50, 53, 56, 59, 62, 65, 68, 71, 74, 77, 80, 83, 86, 89, 92, 95, 98, 101, 104, 107, 110, 113, 116, 119, 122, 125, 128, 131, 134, 137, 140, 143, 146, 149, 152, 155, 158, 161, 164, 167, 170, 173, 176, 179, 182

Offset: 1

Author

Odimar Fabeny, Sep 07 2010

Keywords

• easy
• nonn

Comments

Previous name was "Ceiling(A179896 / n) for n > 0 and remainder <> 0".

Crossrefs

Cf. A000040, A016789, A179545, A179896.

Programs

Maple

From R. J. Mathar, Sep 19 2010: (Start)
A018252 := proc(n) option remember; if n = 1 then 1; else for a from procname(n-1)+1 do if not isprime(a) then return a; end if; end do; end if; end proc:
A045943 := proc(n) 3*n*(n+1)/2 ; end proc:
A179896 := proc(n) A045943(A018252(n)-1) ; end proc:
for n from 1 to 130 do a := A179896(n) ; c := A018252(n) ; if a mod c <> 0 then printf("%d,",ceil(a/c)) ; end if; end do: (End)

Formula

Conjectures from Colin Barker, Nov 25 2019: (Start)

G.f.: x*(5 - 2*x) / (1 - x)^2.

a(n) = 2*a(n-1) - a(n-2) for n>2.

a(n) = 2 + 3*n.

(End)

Extensions

Previous name replaced (with a Sep 19 2010 comments entry from R. J. Mathar) by Jon E. Schoenfield, Nov 28 2019