A323051 Numbers that cannot be written as a sum of two or fewer 11-smooth numbers (A051038).

479, 958, 1151, 1319, 1437, 1559, 1679, 1916, 2302, 2351, 2395, 2638, 2874, 2999, 3013, 3071, 3118, 3353, 3358, 3453, 3671, 3737, 3769, 3832, 3911, 3957, 4199, 4309, 4311, 4604, 4677, 4702, 4703, 4751, 4790, 4919, 5037, 5057, 5269, 5276, 5389, 5443, 5519, 5597, 5683

Offset

1,1

Comments

Similar to A323046 (3-smooth), A323049 (5-smooth) or A323050 (7-smooth).

This sequence is a subsequence of A323046, A323049, and A323050.

Notice that A045535(4) = a(1) = 479.

Links

Table of n, a(n) for n=1..45.

Mathematica

f[n_] := Union@Flatten@Table[2^a*3^b*5^c*7^d, {a, 0, Log2[n]}, {b, 0, Log[3, n/2^a]}, {c, 0, Log[5, n/(2^a*3^b)]}, {d, 0, Log[7, n/(2^a*3^b*5^c)]}];
b = Block[{nn = 3000, s}, s = f[nn]; {0, 1}~Join~
    Select[Union@Flatten@Outer[Plus, s, s], # <= nn &]];
Complement[Range[3000], b]

Crossrefs

See A323046 (3-smooth), A323049 (5-smooth) or A323050 (7-smooth). Cf. A051038, A045535 (or A062241).

Sequence in context: A122268 A186950 A056987 * A025025 A108256 A262222

Adjacent sequences: A323048 A323049 A323050 * A323052 A323053 A323054

Keyword

nonn

Author

Carlos Alves, Jan 03 2019

Status

approved