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A342605 Numbers k such that A342604(k) is prime.

%I A342605 #9 Mar 17 2021 13:25:21
%S A342605 1,2,4,14,20,26,31,39,42,57,64,69,87,92,114,127,150,152,172,213,274,
%T A342605 301,326,379,436,460,499,523,597,708,747,817,819,912,1382,1452,1595,
%U A342605 1600,1603,1632,1647,1670,1768,1833,1834,1873,1890,1986,2137,2696,2702,2859,3080,3154,3167,3173,3386,3933
%N A342605 Numbers k such that A342604(k) is prime.
%H A342605 Robert Israel, <a href="/A342605/b342605.txt">Table of n, a(n) for n = 1..1000</a>
%F A342605 A342604(a(n)) = A342606(n).
%e A342605 a(3) = 4 is a term because A342604(4) = 17 is prime.
%p A342605 p:= 1: R:= NULL:
%p A342605 for n from 0 to 14 do
%p A342605   for k from 0 to n do
%p A342605     p:= nextprime(p);
%p A342605     R:= R, binomial(n,k)*p
%p A342605 od od:
%p A342605 S:= ListTools:-PartialSums([R]):
%p A342605 select(t -> isprime(S[t]), [$1..nops(S)]);
%Y A342605 Cf. A342604, A342606.
%K A342605 nonn
%O A342605 1,2
%A A342605 _J. M. Bergot_ and _Robert Israel_, Mar 16 2021