The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A192180 Composite numbers n such that all digits of n occur in its list of primes. 1
95, 132, 272, 312, 322, 326, 333, 731, 735, 912, 973, 995, 1111, 1212, 1255, 1292, 1972, 2112, 2132, 2232, 2272, 2512, 2672, 2737, 2994, 3171, 3192, 3210, 3212, 3243, 3315, 3393, 3792, 3933, 4172, 4341, 4371, 4383, 5150, 5192, 5271, 6973, 7132, 7210 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
For the purpose here, if a number has repeated prime factors, those are written repeatedly. For example, the factorization of 27 is expressed as (3, 3, 3) rather than (3^3). - Alonso del Arte, Jul 05 2011
LINKS
EXAMPLE
Since the prime factorization of 95 is (5, 19), and both 9 and 5 occur in (5, 19), the number 95 is on the list.
Since the prime factorization of 1255 is (5, 251), and 1, 2, and both 5s occur in (5, 251), the number 1255 is on the list.
22 is not on the list because its prime factorization is (2, 11) and that does not have enough 2s. Nor is 25 on the list because for this sequence we express its factorization as (5, 5) rather than (5^2).
MATHEMATICA
Select[Range[2, 5000], Not[PrimeQ[#]] && Sort[DigitCount[FromDigits[Flatten[IntegerDigits/@Flatten[Table[#1, {#2}]&@@@FactorInteger[#]]]]] - DigitCount[#]][[1]] >= 0 &] (* Alonso del Arte, Jun 28 2011, based on HomePrimeStep function by Eric W. Weisstein *)
PROG
(Magma) S:=[]; for n in [1..10000] do if not IsPrime(n) then u:=Intseq(n); f:=Factorization(n); v:=&cat[ [ f[j, 1]: i in [1..f[j, 2]] ]: j in [1..#f] ]; w:=&cat[ Intseq(p): p in v ]; if forall{ a: a in [0..9] | Multiplicity(SequenceToMultiset(u), a) le Multiplicity(SequenceToMultiset(w), a) } then Append(~S, n); end if; end if; end for; S; // Klaus Brockhaus, Jul 09 2011
CROSSREFS
Cf. A037276.
Sequence in context: A369342 A368873 A074237 * A134217 A039552 A063371
KEYWORD
nonn,base
AUTHOR
Gil Broussard, Jun 24 2011
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 23 10:34 EDT 2024. Contains 372760 sequences. (Running on oeis4.)