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%I #14 Dec 23 2020 19:51:56
%S 1,0,2,4,1,3,7,9,13,19,21,27,31,33,37,43,49,51,57,61,63,69,73,79,87,
%T 91,93,97,99,103,4,8,14,16,26,28,34,40,44,50,56,58,68,70,74,76,88,100,
%U 104,106,110,116,118,128,134,140,146,148,154,158,160,170,184
%N a(n) = (prime(n) + a(n-1)) mod prime(n-1), a(1) = 1.
%e a(2) = (prime(2) + a(1)) mod prime(1) = ( 3 + 1) mod 2 = 0,
%e a(3) = (prime(3) + a(2)) mod prime(2) = ( 5 + 0) mod 3 = 2,
%e a(4) = (prime(4) + a(3)) mod prime(3) = ( 7 + 2) mod 5 = 4,
%e a(5) = (prime(5) + a(4)) mod prime(4) = (11 + 4) mod 7 = 1,
%e a(6) = (prime(6) + a(5)) mod prime(5) = (13 + 1) mod 11 = 3.
%t Nest[Append[#1, Mod[(Prime@ #2 + #1[[-1]]), Prime[#2 - 1]]] & @@ {#, Length[#] + 1} &, {1}, 62] (* _Michael De Vlieger_, Nov 05 2020 *)
%o (Ruby) require 'prime'
%o count = 50
%o primes = Prime.first(count+1)
%o values = [1]
%o count.times { |n| values << (primes[n+1] + values[-1]) % primes[n] }
%o p values
%o (PARI) lista(nn) = {my(va = vector(nn)); va[1] = 1; for (n=2, nn, va[n] = (prime(n) + va[n-1]) % prime(n-1);); va;} \\ _Michel Marcus_, Nov 05 2020
%Y Cf. A000040.
%K nonn
%O 1,3
%A _Simon Strandgaard_, Nov 01 2020
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