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a(n) is the index of the smallest tetranacci number (A000078) with exactly n prime factors (counted with multiplicity).
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%I #8 Jan 19 2023 11:09:26

%S 3,5,6,7,10,11,17,30,20,22,82,60,37,100,236,157,156,242,240

%N a(n) is the index of the smallest tetranacci number (A000078) with exactly n prime factors (counted with multiplicity).

%C a(19) > 400. - _Daniel Suteu_, Jan 18 2023

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PrimeFactor.html">Prime Factor</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TetranacciNumber.html">Tetranacci Number</a>

%Y Cf. A000078, A001222, A072396, A359851, A359877, A359878.

%K nonn,more

%O 0,1

%A _Ilya Gutkovskiy_, Jan 16 2023

%E a(18) from _Daniel Suteu_, Jan 18 2023