A103387 Primes in A103377.

2, 3, 5, 7, 17, 31, 71, 127, 157, 227, 257, 293, 349, 419, 503, 16007, 32783, 33329, 80429, 220919, 786433, 878831, 85790399, 10666238497, 394760836573, 22265159019759079, 617347651958903360669, 98459899570803393815965301

Offset

1,1

Links

Table of n, a(n) for n=1..28.

Formula

Intersection of A103377 with A000040.

Mathematica

SemiprimeQ[n_]:=Plus@@FactorInteger[n][[All, 2]]?2; Clear[a]; k=9; Do[a[n]=1, {n, k+1}]; a[n_]:=a[n]=a[n-k]+a[n-k-1]; A103377=Array[a, 100] A103387=Union[Select[Array[a, 1000], PrimeQ]] A103397=Union[Select[Array[a, 300], SemiprimeQ]] N[Solve[x^10 - x - 1 == 0, x], 111][[2]]

Crossrefs

Cf. A103377, A103397.

Sequence in context: A255161 A103385 A103389 * A103388 A103386 A103384

Adjacent sequences: A103384 A103385 A103386 * A103388 A103389 A103390

Keyword

easy,nonn

Author

Jonathan Vos Post, Feb 15 2005

Status

approved