A035032 For n >= 6, max( prevprime(n), 2*prevprime(floor(n/2))).

1, 2, 2, 3, 3, 5, 5, 7, 7, 7, 7, 11, 11, 13, 13, 14, 14, 17, 17, 19, 19, 19, 19, 23, 23, 23, 23, 26, 26, 29, 29, 31, 31, 31, 31, 34, 34, 37, 37, 38, 38, 41, 41, 43, 43, 43, 43, 47, 47, 47, 47, 47, 47, 53, 53, 53, 53, 53

Offset

1,2

References

S. K. Stein and S. Szabo, Algebra and Tiling, MAA Carus Monograph 25, 1994, page 104.

Links

Table of n, a(n) for n=1..58.

Mathematica

Join[{1, 2, 2, 3, 3}, Table[Max[NextPrime[n, -1], 2*NextPrime[Floor[n/2], -1]], {n, 6, 60}]] (* Harvey P. Dale, Jul 21 2025 *)

Crossrefs

Cf. A035031.

Sequence in context: A340285 A341462 A035031 * A121260 A121261 A085885

Adjacent sequences: A035029 A035030 A035031 * A035033 A035034 A035035

Keyword

nonn

Author

N. J. A. Sloane

Status

approved