A083218 a(n) = n mod (spf(n+1)+1), where spf(n) is the smallest prime factor of n (A020639).

1, 2, 0, 4, 2, 6, 1, 0, 0, 10, 2, 12, 1, 2, 0, 16, 2, 18, 1, 0, 0, 22, 2, 0, 1, 2, 0, 28, 2, 30, 1, 0, 0, 4, 2, 36, 1, 2, 0, 40, 2, 42, 1, 0, 0, 46, 2, 0, 1, 2, 0, 52, 2, 0, 1, 0, 0, 58, 2, 60, 1, 2, 0, 4, 2, 66, 1, 0, 0, 70, 2, 72, 1, 2, 0, 4, 2, 78, 1, 0, 0, 82, 2, 0, 1, 2, 0, 88, 2, 2, 1, 0, 0, 4, 2, 96

Offset

1,2

Comments

a(n) = n iff n+1 is prime: a(A006093(k))=A006093(k).

Links

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

Mathematica

Table[Mod[n, FactorInteger[n+1][[1, 1]]+1], {n, 100}] (* Harvey P. Dale, May 28 2013 *)

Crossrefs

Cf. A057237.

Sequence in context: A097945 A319997 A153733 * A203908 A381214 A334082

Adjacent sequences: A083215 A083216 A083217 * A083219 A083220 A083221

Keyword

nonn

Author

Reinhard Zumkeller, Apr 22 2003

Status

approved