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.

A071924 Highest m such that prime(m) divides the n-th pandigital (A050278).

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%I A071924 #30 Aug 22 2024 05:18:21
%S A071924 749,208,6503705,1831,657,1045880,6503711,239879,375325,7864,45075,
%T A071924 7064,2313602,6503717,59,1766468,78975,840,1046,33355,2133,109,107390,
%U A071924 56057,6503758,3386573,6503759,2044,3386575,158964,2313623,9463,2313625,36081
%N A071924 Highest m such that prime(m) divides the n-th pandigital (A050278).
%H A071924 Chai Wah Wu, <a href="/A071924/b071924.txt">Table of n, a(n) for n = 1..10000</a>
%e A071924 The 10th pandigital 1023457896 has prime decomposition 2^3*3^3*59*80309 and 80309 is indeed the a(10)=7864th prime, i.e., prime(7864)=80309.
%t A071924 PrimePi[FactorInteger[#][[-1,1]]]&/@(Select[Sort[FromDigits/@ Permutations[ Range[0,9]]],IntegerLength[#]>9&,50]) (* _Harvey P. Dale_, Jun 06 2018 *)
%o A071924 (Python)
%o A071924 from itertools import permutations, islice
%o A071924 from sympy import primepi, primefactors
%o A071924 def A071924(n): return primepi(max(primefactors(next(islice((int(e+''.join(d)) for e in '123456789' for d in permutations('0123456789'.replace(e,''),9)),n-1,None))))) # _Chai Wah Wu_, Dec 07 2021
%Y A071924 Cf. A050278.
%K A071924 nonn,base,fini
%O A071924 1,1
%A A071924 _Lekraj Beedassy_, Jun 14 2002
%E A071924 a(24)-a(33) from _Donovan Johnson_, Jan 25 2009
%E A071924 Edited by _Charles R Greathouse IV_, Aug 02 2010
%E A071924 Keyword "fini" added by _Sean A. Irvine_, Aug 21 2024