A117563 a(n) = A118534(n)/A117078(n) unless A117078(n) = 0 in which case a(n) = 0.

0, 0, 1, 0, 3, 1, 5, 3, 1, 9, 1, 3, 13, 3, 1, 1, 19, 5, 9, 23, 1, 15, 11, 9, 3, 33, 11, 35, 21, 3, 3, 5, 45, 3, 49, 5, 1, 3, 23, 1, 59, 9, 63, 27, 65, 11, 1, 3, 75, 45, 1, 79, 21, 35, 1, 1, 89, 5, 39, 93, 21, 9, 3, 103, 3, 3, 25, 3, 115, 69, 1, 39, 19, 1, 75, 29, 3, 3, 3, 21, 139, 3, 143, 61, 87

Offset: 1

Author

Rémi Eismann, Apr 29 2006, Feb 14 2008

Keywords

• nonn

Comments

a(n) is the "level" of prime(n).

There is a unique decomposition of the primes: provided the level a(n) is > 0, we have prime(n) = weight * level + gap, or A000040(n)=A117078(n)*a(n)+A001223(n).

a(n) = 0 only for primes 2, 3 and 7.

A118534(n) = prime(n) - g(n) or A000040(n) - A001223(n) if prime(n) - g(n) > g(n), 0 otherwise.

Examples

			a(7)=15/3=5; a(14)=39/13=3; a(16)=47/47=1; a(18)=55/11=5; a(29)=105/5=11.
		

Links

• Remi Eismann, Table of n, a(n) for n = 1..10000
• Remi Eismann, Java program to decompose a prime as weight*level + gap, or A117078(n)*A117563(n) + A001223(n).
• Rémi Eismann, Decomposition into weight * level + jump and application to a new classification of primes, arXiv:0711.0865 [math.NT], 2007-2010.

Crossrefs

Cf. A117078, A118534.

Programs

Mathematica

a34[n_] := If[n == 1 || n == 2 || n == 4, 0, 2 Prime[n] - Prime[n+1]];
a78[n_] := Block[{a, p = Prime[n], np = Prime[n+1]}, a = Min[Select[ Divisors[2p - np], # > np - p& ]]; If[a == Infinity, 0, a]];
a[n_] := If[a78[n] == 0, 0, a34[n]/a78[n]];
Array[a, 85] (* Jean-François Alcover, Nov 02 2018, after Robert G. Wilson v in A118534  *)

Extensions

More terms from Robert G. Wilson v, May 05 2006

Edited by N. J. A. Sloane, May 14 2006