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Composite numbers all of whose divisors except the divisor 1 have a prime digital sum.
1

%I #11 Nov 13 2019 09:32:52

%S 14,21,25,49,58,94,98,115,122,166,201,203,205,274,278,287,302,319,335,

%T 346,382,386,427,445,454,458,469,517,526,562,566,575,623,634,667,674,

%U 685,706,737,746,755,791,818,841,854,865,913,917,922,926,955,959,973

%N Composite numbers all of whose divisors except the divisor 1 have a prime digital sum.

%C Noteworthy members of this sequence are: 854, 38525 and 166286 because they have 7, 11 and 15 divisors with a prime digital sum.

%H Amiram Eldar, <a href="/A093994/b093994.txt">Table of n, a(n) for n = 1..10000</a>

%e a(2)=21 because its divisors are [1, 3, 7, 21] all (except 1) of which have prime digital sums.

%t digQ[n_] := PrimeQ @ Total @ IntegerDigits[n]; aQ[n_] := CompositeQ[n] && AllTrue[Rest @ Divisors[n], digQ]; Select[Range[1000], aQ] (* _Amiram Eldar_, Nov 13 2019 *)

%K base,easy,nonn

%O 1,1

%A _Jason Earls_, May 24 2004