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.

A062671 Every divisor (except 1) contains the digit 5.

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%I A062671 #20 Sep 08 2022 08:45:03
%S A062671 5,25,53,59,125,151,157,251,257,265,295,353,359,457,503,509,521,523,
%T A062671 541,547,557,563,569,571,577,587,593,599,625,653,659,751,755,757,785,
%U A062671 853,857,859,953,1051,1151,1153,1255,1259,1285,1325,1451,1453,1459,1475,1511
%N A062671 Every divisor (except 1) contains the digit 5.
%H A062671 Amiram Eldar, <a href="/A062671/b062671.txt">Table of n, a(n) for n = 1..10000</a>
%e A062671 25 has divisors 1, 5 and 25, all of which (except 1) contain the digit 5.
%t A062671 fQ[n_, dgt_] := Union[ MemberQ[#, dgt] & /@ IntegerDigits@ Rest@ Divisors@ n][[1]]; Select[ Range[2, 1500], fQ[#, 5] &] (* _Robert G. Wilson v_, Jun 11 2014 *)
%o A062671 (Magma) [k:k in [2..1500]| forall{d:d in Set(Divisors(k)) diff {1}| 5 in Intseq(d)}]; // _Marius A. Burtea_, Nov 07 2019
%o A062671 (Python)
%o A062671 from sympy import divisors
%o A062671 def ok(n): return all('5' in str(d) for d in divisors(n)[1:])
%o A062671 print(list(filter(ok, range(2, 1512)))) # _Michael S. Branicky_, May 25 2021
%Y A062671 Cf. A062653, A062664, A062667, A062668, A062669, A062670, A062672, A062673, A062674, A062675, A062676, A062677, A062678, A062679, A062680.
%K A062671 base,easy,nonn
%O A062671 1,1
%A A062671 _Erich Friedman_, Jul 04 2001
%E A062671 Offset corrected by _Amiram Eldar_, Nov 07 2019