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A081332 Numbers having a unique partition into two 3-smooth numbers. 2
2, 3, 29, 31, 37, 41, 43, 49, 55, 58, 59, 62, 65, 67, 74, 83, 85, 86, 87, 89, 91, 93, 98, 109, 110, 111, 113, 116, 118, 123, 124, 130, 131, 134, 137, 147, 148, 155, 163, 165, 166, 170, 172, 174, 177, 178, 182, 186, 193, 195, 196, 201, 209, 217, 218, 220, 222, 226 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

A081326(a(n)) = 1.

MATHEMATICA

nmax = 1000;

S = Select[Range[nmax], Max[FactorInteger[#][[All, 1]]] <= 3 &];

P[n_] := IntegerPartitions[n, {2}, TakeWhile[S, # < n &]];

selQ[n_] := Length[P[n]] == 1;

Select[Range[nmax], selQ] (* Jean-Fran├žois Alcover, Oct 14 2021 *)

CROSSREFS

Cf. A003586, A081326, A081333, A081330.

Sequence in context: A096580 A324941 A028868 * A106868 A098419 A041193

Adjacent sequences:  A081329 A081330 A081331 * A081333 A081334 A081335

KEYWORD

nonn,changed

AUTHOR

Reinhard Zumkeller, Mar 19 2003

STATUS

approved

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Last modified October 18 01:39 EDT 2021. Contains 348065 sequences. (Running on oeis4.)