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.

A383114 Triprimes that are concatenations of three consecutive primes.

Original entry on oeis.org

357, 131719, 434753, 475359, 717379, 97101103, 101103107, 103107109, 109113127, 139149151, 151157163, 157163167, 163167173, 167173179, 173179181, 193197199, 197199211, 199211223, 227229233, 241251257, 281283293, 293307311, 331337347, 347349353, 367373379, 397401409, 461463467, 487491499
Offset: 1

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Author

Will Gosnell and Robert Israel, May 23 2025

Keywords

Comments

Numbers that are the concatenation (in increasing order) of three consecutive primes and are the product of three primes, counted with multiplicity.

Examples

			a(3) = 434753 is a term because it is the concatenation of the consecutive primes 43, 47 and 53 and 434753 = 11^2 * 3593 is the product of three primes, counted with multiplicity.
		

Crossrefs

Intersection of A014612 and A132903.

Programs

  • Maple
    cat3:= proc(a,b,c)
      (a*10^(1+ilog10(b))+b)*10^(1+ilog10(c))+c
    end proc:
    select(t ->numtheory:-bigomega(t)=3, [seq(cat3(ithprime(i),ithprime(i+1),ithprime(i+2)),i=1..100)]);
  • Mathematica
    p3[p_]:=FromDigits[Join[IntegerDigits[Prime[p]],IntegerDigits[Prime[p+1]],IntegerDigits[Prime[p+2]]]];Select[Array[p3,100],PrimeOmega[#]==3&] (* James C. McMahon, Jun 09 2025 *)