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.

A335969 Sphenic numbers that are also the sum of three consecutive primes.

Original entry on oeis.org

1015, 1533, 1645, 2233, 2737, 2915, 3219, 3515, 3745, 3815, 4301, 4503, 4565, 4623, 4697, 4921, 5289, 5621, 6055, 6095, 6213, 6251, 6409, 7055, 7347, 7657, 7847, 8099, 8455, 8569, 8687, 8729, 9499, 9581, 9955, 10105, 10153, 10295, 10735, 11155, 11297, 11315, 11803, 12665, 12805, 12845
Offset: 1

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Author

Zak Seidov, Jul 04 2020

Keywords

Comments

Intersection of A007304 and A034961.
Includes 15*p where p, 5*p-14, 5*p-2 and 5*p+16 are consecutive primes. Dickson's conjecture implies there are infinitely many such terms. - Robert Israel, Nov 24 2022

Examples

			1015 = A007304(140) = A034961(67), 1533 = A007304(226) = A034961(96).
		

Crossrefs

Programs

  • Maple
    P:= select(isprime, [seq(i,i=3..10^4,2)]):
    P3:= P[1..-3] + P[2..-2] + P[3..-1]:
    filter:= proc(t) local F; F:= ifactors(t)[2]; nops(F) = 3 and F[1,2]=1 and F[2,2] = 1 and F[3,2]=1 end proc:
    select(filter, P3); # Robert Israel, Nov 24 2022
  • Mathematica
    Intersection[ Select[Range[105, 40000,2], 3 == PrimeOmega[#] == PrimeNu[#] &], Total /@ Partition[Prime[Range[40000]], 3, 1]]