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

1,2

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

Formula

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

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 *)

Crossrefs

Cf. A141468, A066110, A001223

Sequence in context: A214878 A086138 A170822 * A065310 A226352 A238402

Adjacent sequences: A054543 A054544 A054545 * A054547 A054548 A054549

Keyword

nonn,easy

Author

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

Extensions

More terms from James A. Sellers, Apr 11 2000

Status

approved