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

749, 208, 6503705, 1831, 657, 1045880, 6503711, 239879, 375325, 7864, 45075, 7064, 2313602, 6503717, 59, 1766468, 78975, 840, 1046, 33355, 2133, 109, 107390, 56057, 6503758, 3386573, 6503759, 2044, 3386575, 158964, 2313623, 9463, 2313625, 36081

Offset

1,1

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Example

The 10th pandigital 1023457896 has prime decomposition 2^3*3^3*59*80309 and 80309 is indeed the a(10)=7864th prime, i.e., p(7864)=80309.

Mathematica

PrimePi[FactorInteger[#][[-1, 1]]]&/@(Select[Sort[FromDigits/@ Permutations[ Range[0, 9]]], IntegerLength[#]>9&, 50]) (* Harvey P. Dale, Jun 06 2018 *)

Prog

(Python)
from itertools import permutations, islice
from sympy import primepi, primefactors
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

Crossrefs

Cf. A050278.

Sequence in context: A242150 A184024 A263381 * A078549 A252524 A252525

Adjacent sequences: A071921 A071922 A071923 * A071925 A071926 A071927

Keyword

nonn,base

Author

Lekraj Beedassy, Jun 14 2002

Extensions

a(24)-a(33) from Donovan Johnson, Jan 25 2009

Edited by Charles R Greathouse IV, Aug 02 2010

Status

approved