A054546 First differences of nonprimes (including 0 and 1, A002808).

1, 3, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 2

Offset: 1

Author

G. L. Honaker, Jr., Apr 09 2000

Keywords

• nonn
• easy

Comments

Sum of first n terms equals n-th nonprime number.

First differences of A141468. - Omar E. Pol, Oct 21 2011

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A141468, A066110, A001223

Programs

Mathematica

t=Flatten[Position[Table[PrimeQ[w], {w, 2, 256}], False]]+1 Delete[t-RotateRight[t], 1]
Differences[Select[Range[0,200],!PrimeQ[#]&]] (* Harvey P. Dale, May 27 2018 *)

Formula

a(n) = A018252(n) - A141468(n). - Omar E. Pol, Oct 21 2011

Extensions

More terms from James Sellers, Apr 11 2000