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a(1) = 2. a(n) = a(n-1)*(largest prime occurring earlier in the sequence) - 1.
1

%I #11 Nov 16 2024 17:29:22

%S 2,3,8,23,528,12143,147452448,1790515076063,21742224568633008,

%T 264015832936910616143,3205944259352905611824448,

%U 38929781141322332844384272063,472724332399077087729358215661008,5740291568321993076297596812771620143

%N a(1) = 2. a(n) = a(n-1)*(largest prime occurring earlier in the sequence) - 1.

%e Among the first 4 terms of the sequence, 23 is the largest prime. So a(5) = a(4)*23 -1 = 23*23 -1 = 528.

%o (PARI) {m=13;print1(a=2,",");v=[a];for(n=2,m,b=a;v=vecsort(v);j=#v;a=0;while(a<1,k=v[j];if(isprime(k),print1(a=b*k-1,",");v=concat(v,a),j--)))} \\ _Klaus Brockhaus_, Aug 17 2006

%Y Cf. A120762.

%K nonn,changed

%O 1,1

%A _Leroy Quet_, Jul 03 2006

%E More terms from _Klaus Brockhaus_, Aug 17 2006.

%E a(14) added by _Robert C. Lyons_, Nov 16 2024.