A383471 a(n) = round(Product_{k=1..n} (1 + 1/2^2^(-k))).
1, 2, 3, 6, 12, 23, 46, 93, 185, 370, 739, 1478, 2955, 5910, 11819, 23637, 47274, 94549, 189097, 378194, 756388, 1512776, 3025551, 6051102, 12102203, 24204407, 48408813, 96817626, 193635251, 387270501, 774541003, 1549082005, 3098164010, 6196328019, 12392656038, 24785312075
Offset: 0
Keywords
Programs
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Mathematica
Floor[Product[(1+2^(-2^(-k))),{k,1,n}]+1/2] -
PARI
a(n) = round(prod(k=1, n, 1 + 1/2^2^(-k))); \\ Michel Marcus, Apr 28 2025