A127066 a(0)=1; for n > 0, a(n) = a(n-1) + a(prime(n)(mod n)), where prime(n) is the n-th prime.

1, 2, 4, 8, 16, 18, 20, 28, 36, 54, 108, 162, 164, 168, 170, 174, 192, 228, 256, 364, 526, 634, 802, 972, 1200, 2002, 2974, 3776, 4748, 5550, 6522, 6530, 6538, 6556, 6564, 6618, 6646, 6700, 6862, 7024, 7192, 7366, 7534, 7898, 8126, 8354, 8528, 9500, 16030

Offset: 0

Author

Leroy Quet, Mar 21 2007

Keywords

• nonn

Examples

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

Crossrefs

Cf. A004648, A127064.

Programs

Maple

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

Mathematica

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 *)

Extensions

More terms from Emeric Deutsch and Ray Chandler, Mar 23 2007