cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A067173 Numbers n such that the sum of the prime factors of n equals the product of the digits of n.

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%I A067173 #10 Apr 23 2017 04:14:08
%S A067173 2,3,5,7,126,154,315,329,342,418,442,1134,1826,2354,3383,4343,5282,
%T A067173 5561,6623,7515,7922,9331,9911,12773,13344,14161,15194,17267,18292,
%U A067173 21479,22831,26216,26522,29812,32129,33128,33912,57721,81191,81524
%N A067173 Numbers n such that the sum of the prime factors of n equals the product of the digits of n.
%H A067173 Giovanni Resta, <a href="/A067173/b067173.txt">Table of n, a(n) for n = 1..10000</a> (first 184 terms from Harvey P. Dale)
%e A067173 The prime factors of 315 are 3,5,7, which sum to 15, the product of the digits of 315, so 315 is a term of the sequence.
%t A067173 f[n_] := Module[{a, l, t, r}, a = FactorInteger[n]; l = Length[a]; t = Table[a[[i]][[1]], {i, 1, l}]; r = Sum[t[[i]], {i, 1, l}]]; g[n_] := Module[{b, m, s}, b = IntegerDigits[n]; m = Length[b]; s = Product[b[[i]], {i, 1, m}]]; Select[Range[10^5], f[ # ] == g[ # ] &]
%t A067173 Select[Range[2,100000],Total[FactorInteger[#][[All,1]]] == Times@@ IntegerDigits[ #]&] (* _Harvey P. Dale_, Feb 15 2017 *)
%Y A067173 Cf. A065774, A006753.
%K A067173 base,nonn
%O A067173 1,1
%A A067173 _Joseph L. Pe_, Feb 18 2002