A318487 - OEIS

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

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OFFSET

1,1

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.

LINKS

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

EXAMPLE

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

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 *)

CROSSREFS

Cf. A000959, A032639, A303403.

Sequence in context: A026411 A020189 A166986 * A047233 A194382 A296655

Adjacent sequences: A318484 A318485 A318486 * A318488 A318489 A318490

KEYWORD

nonn

AUTHOR

Amiram Eldar, Aug 27 2018

STATUS

approved