A370999 Least composite number k such that the number m of consecutive composite sums k + j*(j+1)/2, j = 1, ..., m is a new maximum.

4, 8, 9, 15, 24, 90, 105, 114, 225, 264, 300, 945, 5349, 7035, 11739, 17280, 35475, 46914, 190365, 351645, 603054, 1209900, 3146220, 3279864, 6407664, 26447649, 115192665, 408291345, 1080430119, 1298351109, 6459163344, 7731193299, 8096124894, 8884256514, 18927105834

Offset: 1

Author

Karl-Heinz Hofmann and Hugo Pfoertner, Mar 09 2024

Keywords

• nonn

Comments

a(60) > 10^15.

Links

• Karl-Heinz Hofmann and Hugo Pfoertner, Table of n, a(n) for n = 1..59
• IBM Research, Composite Sequences, Ponder This Challenge March 2024.

Crossrefs

A371000 gives the corresponding counts m.

Cf. A000217, A371001, A371002.

Extensions

a(43) in b-file corrected by Kebbaj Mohamed Reda, May 29 2024