A127066 - OEIS

%I #15 Feb 01 2019 03:03:36

%S 1,2,4,8,16,18,20,28,36,54,108,162,164,168,170,174,192,228,256,364,

%T 526,634,802,972,1200,2002,2974,3776,4748,5550,6522,6530,6538,6556,

%U 6564,6618,6646,6700,6862,7024,7192,7366,7534,7898,8126,8354,8528,9500,16030

%N a(0)=1; for n > 0, a(n) = a(n-1) + a(prime(n)(mod n)), where prime(n) is the n-th prime.

%e The 7th prime, 17, is congruent to 3 (mod 7). So a(7) = a(6) + a(3) = 20 + 8 = 28.

%p a:=proc(n) if n=0 then 1 else a(n-1)+a(ithprime(n) mod n) fi end: seq(a(n),n=0..55); # _Emeric Deutsch_, Mar 23 2007

%t f[l_List] := Block[{n = Length[l]},Append[l, l[[Mod[Prime[n], n] + 1]] + l[[ -1]]]]; Nest[f, {1}, 50] (* _Ray Chandler_, Mar 23 2007 *)

%Y Cf. A004648, A127064.

%K nonn

%O 0,2

%A _Leroy Quet_, Mar 21 2007

%E More terms from _Emeric Deutsch_ and _Ray Chandler_, Mar 23 2007