A318487 Even numbers that are not the sum of two lucky-indexed lucky numbers.

4, 6, 10, 12, 16, 18, 20, 24, 26, 30, 34, 36, 40, 44, 46, 48, 54, 58, 60, 66, 68, 72, 74, 76, 78, 82, 86, 90, 92, 96, 100, 102, 104, 106, 110, 114, 116, 120, 122, 124, 128, 130, 134, 138, 140, 144, 146, 152, 154, 156, 158, 164, 168, 170, 176, 178, 182, 184

Offset: 1

Author

Amiram Eldar, Aug 27 2018

Keywords

• nonn

Comments

Conjecture (checked up to 10^7): every even number larger than 199254 is the sum of two lucky-indexed lucky numbers, so this sequence is finite with 1714 terms.

Examples

			28 is not in this sequence since 28 = 7 + 21 and 7 and 21 are lucky-indexed lucky numbers (A032639).
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1714

Crossrefs

Cf. A000959, A032639, A303403.

Programs

Mathematica

L = Table[2*i + 1, {i, 0, 150000}]; For[n = 2, n < Length[L], r = L[[n++]]; L = ReplacePart[L, Table[r*i -> Nothing, {i, 1, Length[L]/r}]]]; a = L[[Select[L, # <= Length[L] &]]]; v = Select[Range[2, 300000, 2], IntegerPartitions[#, {2}, a] == {} &]; (* after Jean-François Alcover at A000959 and Giovanni Resta at A303403 *)