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a(n) = A062402(2^n+1).
4

%I #12 Jun 04 2024 01:26:12

%S 1,3,7,12,31,42,124,224,511,847,1953,2688,12264,18816,29127,72540,

%T 131071,195048,558523,1077440,3164112,4552020,10890040,10342080,

%U 54525848,73260781,155671040,318848400,1080311232,964580240,3070642080,4340711424,13722819600,19039027200

%N a(n) = A062402(2^n+1).

%H Amiram Eldar, <a href="/A096856/b096856.txt">Table of n, a(n) for n = 0..372</a>

%F a(n) = A000203(A053285(n)). - _Amiram Eldar_, Jun 04 2024

%t Table[DivisorSigma[1, EulerPhi[2^n + 1]], {n, 0, 30}]

%Y Cf. A000203, A053285, A062401, A062402, A053287, A096853, A096854, A096855.

%K nonn

%O 0,2

%A _Labos Elemer_, Jul 19 2004

%E Offset changed to 0, a(0) prepended and three more terms added by _Amiram Eldar_, Jun 04 2024