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A273157 Numbers which have nonpositive entries in the difference table of their divisors (complement of A273130).

%I A273157 #19 Feb 27 2020 11:51:56
%S A273157 6,10,12,14,15,18,20,22,24,26,28,30,34,35,36,38,40,42,44,45,46,48,50,
%T A273157 52,54,56,58,60,62,63,66,68,70,72,74,75,76,77,78,80,82,84,86,88,90,91,
%U A273157 92,94,96,98,99,100,102,104,105,106,108,110,112,114,116,117
%N A273157 Numbers which have nonpositive entries in the difference table of their divisors (complement of A273130).
%C A273157 Primorial numbers (A002110) greater than 2 are in this sequence.
%e A273157 30 is in this sequence because the difference table of the divisors of 30 is:
%e A273157 [1, 2, 3, 5, 6, 10, 15, 30]
%e A273157 [1, 1, 2, 1, 4, 5, 15]
%e A273157 [0, 1, -1, 3, 1, 10]
%e A273157 [1, -2, 4, -2, 9]
%e A273157 [-3, 6, -6, 11]
%e A273157 [9, -12, 17]
%e A273157 [-21, 29]
%e A273157 [50]
%o A273157 (Sage)
%o A273157 def nsf(z):
%o A273157     D = divisors(z)
%o A273157     T = matrix(ZZ, len(D))
%o A273157     for m, d in enumerate(D):
%o A273157         T[0, m] = d
%o A273157         for k in range(m-1, -1, -1) :
%o A273157             T[m-k, k] = T[m-k-1, k+1] - T[m-k-1, k]
%o A273157             if T[m-k, k] <= 0: return True
%o A273157     return False
%o A273157 print([n for n in range(1, 100) if nsf(n)])
%Y A273157 Cf. A069059, A187202, A273102, A273103, A273109, A273130 (complement).
%K A273157 nonn
%O A273157 1,1
%A A273157 _Peter Luschny_, May 16 2016