A091237 Lengths of runs in A039702.

1, 1, 1, 2, 2, 2, 1, 1, 2, 2, 1, 1, 1, 2, 1, 2, 3, 2, 2, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 4, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 1, 2, 2, 1, 2, 4, 1, 1, 1, 1, 2, 3, 7, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 2, 1, 1, 3, 2, 2, 2, 1, 3, 4

Offset: 1

Author

N. J. A. Sloane, Feb 22 2004

Keywords

• nonn
• easy

Comments

Lengths of runs, where a run is a succession of primes that are congruent mod 4.

In other words, RUNS transform of A039702. If the two initial 1's are omitted, this is the RUNS transform of A100672. - N. J. A. Sloane, Jan 11 2025

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A039702, A091318, A091267, A100672.

Programs

Mathematica

Most[Length /@ Split[Table[Mod[Prime[n], 4], {n, 200}]]] (* T. D. Noe, Sep 21 2012 *)

Extensions

More terms from David Wasserman, Feb 28 2006