

A081313


Numbers having more than one representation as sum of a prime and a 3smooth number.


4



4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 49, 50, 51, 53, 55, 56, 57, 59, 61, 62, 63, 64, 65, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 79, 80, 81, 82, 83, 84, 85, 86
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OFFSET

1,1


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000


FORMULA

A081308(a(n)) > 1.


MATHEMATICA

nmax = 1000;
S = Select[Range[nmax], Max[FactorInteger[#][[All, 1]]] <= 3 &];
A081308[n_] := Count[TakeWhile[S, # < n &], s_ /; PrimeQ[n  s]];
Select[Range[nmax], A081308[#] > 1 &] (* JeanFrançois Alcover, Oct 13 2021 *)


PROG

(Haskell)
a081313 n = a081313_list !! (n1)
a081313_list = filter ((> 1) . a081308) [1..]
 Reinhard Zumkeller, Jul 04 2012


CROSSREFS

Cf. A000040, A003586, A081308, A081312.
Subsequence of A081311.
Sequence in context: A171526 A171463 A020705 * A227983 A081333 A026419
Adjacent sequences: A081310 A081311 A081312 * A081314 A081315 A081316


KEYWORD

nonn


AUTHOR

Reinhard Zumkeller, Mar 17 2003


STATUS

approved



