%I #7 Dec 05 2013 19:56:46

%S 3,2,3,17,5,13,7,17,19,29,11,73,13,29,31,41,17,37,19,41,43,53,23,73,

%T 31,53,29,137,29,61,31,73,67,149,71,73,37,101,79,89,41,109,43,89,47,

%U 101,47,97,107,101,103,113,53,109,61,113,59,197,59,241,61,149,127,137,131,157

%N Beginning with n, add the next number, subtract the previous number and so on until one gets a prime, or 0 if no such prime is reached in 2n-1 steps: a(n) = n + (n+1) - (n-1) +(n+2) -(n-2) +(n+3)-(n-3)...+...is the first occurring prime at any step.

%C a(p) = p, p is a prime. If the process is continued until a 1 is subtracted the result is n^2. Conjecture: No term is zero.

%F The k-th step of the process used to generate the n-th term is 2n+(k^2)/4 if k is even and n+(k^2-1)/4 if k is odd. - Adam M. Kalman (mocha(AT)clarityconnect.com), Nov 09 2004

%e a(4) = 17 and the steps are 4, 4+5, 4+5-3, 4+5-3+6, 4+5-3+6-2, 4+5-3+6-2+7= 17. a(6) = 6+7 =13.

%t For[a=1, a<100, x:=a;s:=1; While[(!PrimeQ[x])\[And](s<=2a-1), If[OddQ[s], x+=a+(s+1)/2, x+=-a+s/2];s++ ]; If[PrimeQ[x], Print[x], Print[0]];a++ ]; (Kalman)

%Y Cf. A092951, A092952.

%K nonn

%O 1,1

%A _Amarnath Murthy_, Mar 24 2004

%E More terms from Adam M. Kalman (mocha(AT)clarityconnect.com), Nov 09 2004