A262996 Ten-digit semiprimes with exactly one 1, two 2's, three 3's and four 4's.

1223444433, 1224343443, 1233444243, 1233444423, 1234424343, 1234442343, 1243344243, 1243442433, 1244332443, 1244343423, 1244344323, 1244442333, 1323442443, 1324244433, 1324344423, 1324443243, 1324443423, 1324444323, 1332244443, 1334244243, 1334244423, 1334424243, 1342443243, 1343242443

Offset

1,1

Comments

From total 10!/(2!*3!*4!)=12600 ten-digit numbers with exactly one 1, two 2's, three 3's and four 4's, exactly 732 numbers are semiprimes of the form 3*prime.

Links

Zak Seidov, Table of n, a(n) for n = 1..732

Mathematica

Select[(FromDigits[#] & /@ Permutations[{1, 2, 2, 3, 3, 3, 4, 4, 4, 4}]), PrimeQ[#/3] &]

Prog

(PARI) forprime(p=407814811, 1481443741, d=digits(3*p); if(vecsort(d)==[1, 2, 2, 3, 3, 3, 4, 4, 4, 4], print1(3*p", "))) \\ Charles R Greathouse IV, Sep 24 2015

Crossrefs

Cf. A022915.

Sequence in context: A119333 A309227 A195988 * A022250 A344365 A211770

Adjacent sequences: A262993 A262994 A262995 * A262997 A262998 A262999

Keyword

nonn,base,fini,full

Author

Zak Seidov, Oct 07 2015

Status

approved