cp's OEIS Frontend

A097227 Numbers m such that m = prime(d_1) * prime(d_2) * ... * prime(d_k), where d_1 d_2 ... d_k is the decimal expansion of m.

%I A097227 #33 May 05 2022 04:43:49
%S A097227 14,154,1196,279174
%N A097227 Numbers m such that m = prime(d_1) * prime(d_2) * ... * prime(d_k), where d_1 d_2 ... d_k is the decimal expansion of m.
%C A097227 a(n) !== 1 (mod 10). No other terms below 10^44. - _Chai Wah Wu_, Aug 10 2017
%e A097227 279174 = prime(2)*prime(7)*prime(9)*prime(1)*prime(7)*prime(4) so 279174 is in the sequence.
%t A097227 v={}; Do[h=IntegerDigits[n]; l=Length[h]; p=Product[h[[k]], {k, l}]; If[p>0&&Product[Prime[h[[k]]], {k, l}]==n, v=Append[v, n]; Print[v]], {n, 40000000}]
%o A097227 (Python)
%o A097227 from functools import reduce
%o A097227 from operator import mul
%o A097227 from itertools import combinations_with_replacement
%o A097227 A097227_list, ptuple = [], (2,3,5,7,11,13,17,19,23)
%o A097227 for l in range(1,12):
%o A097227     for d in combinations_with_replacement(range(1,10),l):
%o A097227         n = reduce(mul,(ptuple[i-1] for i in d))
%o A097227         if n < 10**l and tuple(sorted((int(x) for x in str(n)))) == d:
%o A097227             A097227_list.append(n) # _Chai Wah Wu_, Aug 10 2017
%Y A097227 Cf. A097228.
%Y A097227 Subsequence of A329711.
%K A097227 base,more,nonn
%O A097227 1,1
%A A097227 _Farideh Firoozbakht_, Aug 12 2004