This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A223893 #15 Mar 29 2013 13:40:15 %S A223893 0,1,1,0,2,0,2,1,1,2,1,2,2,2,2,3,1,4,3,4,3,4,3,5,3,5,3,4,4,5,6,5,5,5, %T A223893 5,7,6,5,7,4,7,7,8,7,7,6,10,8,9,9,8,7,12,8,12,8,10,6,14,9,15,8,13,7, %U A223893 14,11,16,8,14,7,19,11,19,10,15,9,21,12,20,11,18 %N A223893 Number of partitions of n into at most three distinct primes. %C A223893 The sequence shows a stronger version of the Goldbach conjecture that for n > 6, n has partitions with at most three distinct primes. %H A223893 T. D. Noe, <a href="/A223893/b223893.txt">Table of n, a(n) for n = 1..1000</a> %e A223893 a(21)=3 as 21 = 2+19 = 3+5+13 = 3+7+11. %t A223893 a[n_] := Length@Select[IntegerPartitions[n, 3, Prime@Range@PrimePi@n], %t A223893 Sort@#==Union@# &]; Array[a, 100] (* _Giovanni Resta_, Mar 29 2013 *) %Y A223893 Cf. A000586, A000607, A071335, A185101, A218007, A218469. %K A223893 nonn %O A223893 1,5 %A A223893 _Frank M Jackson_, Mar 28 2013