A108585 -id:A108585 - cp's OEIS frontend

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A108583 Primes of the form 1 + Product_{j=1..k} b(j), where b(n) = b(n-1) + 2*A005185(n) and b(1) = 2.

Original entry on oeis.org

3, 13, 2593, 2426113

Offset: 0

Roger L. Bagula, Jul 05 2005

Next term contains 886 digits. - G. C. Greubel, Dec 19 2022

G. C. Greubel, Table of n, a(n) for n = 0..4

Cf. A005185, A108585.

Hofstadter[n_]:= Hofstadter[n]= If[n<2, 1, Hofstadter[n-Hofstadter[n- 1]] +Hofstadter[n-Hofstadter[n-2]]]; (* A005185 *)
b[n_]:= b[n]= If[n==1, 2, b[n-1] +2*Hofstadter[n]]; (* A108585 *)
p[n_]:= p[n]= Product[b[j], {j,n}];
Select[Table[p[n] +1, {n, 500}], PrimeQ]

Edited by G. C. Greubel, Dec 19 2022

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