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 A182714 #64 May 16 2020 01:31:09 %S A182714 0,0,0,1,0,1,1,3,2,5,5,10,10,17,19,31,34,51,60,86,100,139,165,223,265, %T A182714 349,418,543,648,827,992,1251,1495,1866,2230,2758,3289,4033,4803,5852, %U A182714 6949,8411,9973,12005,14194,17002,20060,23919,28153,33426,39256,46438 %N A182714 Number of 4's in the last section of the set of partitions of n. %C A182714 Zero together with the first differences of A024788. %C A182714 Also number of 4's in all partitions of n that do not contain 1 as a part. %C A182714 a(n) is the number of partitions of n such that m(1) < m(3), where m = multiplicity; e.g., a(7) counts these 3 partitions: [4, 3], [3, 3, 1], [3, 2, 2]. - _Clark Kimberling_, Apr 01 2014 %C A182714 The last section of the set of partitions of n is also the n-th section of the set of partitions of any integer >= n. - _Omar E. Pol_, Apr 07 2014 %H A182714 Alois P. Heinz, <a href="/A182714/b182714.txt">Table of n, a(n) for n = 1..1000</a> %F A182714 It appears that A000041(n) = a(n+1) + a(n+2) + a(n+3) + a(n+4), n >= 0. - _Omar E. Pol_, Feb 04 2012 %e A182714 a(8) = 3 counts the 4's in 8 = 4+4 = 4+2+2. The 4's in 8 = 4+3+1 = 4+2+1+1 = 4+1+1+1+1 do not count. %e A182714 From _Omar E. Pol_, Oct 25 2012: (Start) %e A182714 -------------------------------------- %e A182714 Last section Number %e A182714 of the set of of %e A182714 partitions of 8 4's %e A182714 -------------------------------------- %e A182714 8 .............................. 0 %e A182714 4 + 4 .......................... 2 %e A182714 5 + 3 .......................... 0 %e A182714 6 + 2 .......................... 0 %e A182714 3 + 3 + 2 ...................... 0 %e A182714 4 + 2 + 2 ...................... 1 %e A182714 2 + 2 + 2 + 2 .................. 0 %e A182714 . 1 .......................... 0 %e A182714 . 1 ...................... 0 %e A182714 . 1 ...................... 0 %e A182714 . 1 .................. 0 %e A182714 . 1 ...................... 0 %e A182714 . 1 .................. 0 %e A182714 . 1 .................. 0 %e A182714 . 1 .............. 0 %e A182714 . 1 .................. 0 %e A182714 . 1 .............. 0 %e A182714 . 1 .............. 0 %e A182714 . 1 .......... 0 %e A182714 . 1 .......... 0 %e A182714 . 1 ...... 0 %e A182714 . 1 .. 0 %e A182714 ------------------------------------ %e A182714 . 6 - 3 = 3 %e A182714 . %e A182714 In the last section of the set of partitions of 8 the difference between the sum of the fourth column and the sum of the fifth column is 6 - 3 = 3 equaling the number of 4's, so a(8) = 3 (see also A024788). %e A182714 (End) %p A182714 b:= proc(n, i) option remember; local g, h; %p A182714 if n=0 then [1, 0] %p A182714 elif i<2 then [0, 0] %p A182714 else g:= b(n, i-1); h:= `if`(i>n, [0, 0], b(n-i, i)); %p A182714 [g[1]+h[1], g[2]+h[2]+`if`(i=4, h[1], 0)] %p A182714 fi %p A182714 end: %p A182714 a:= n-> b(n, n)[2]: %p A182714 seq (a(n), n=1..70); # _Alois P. Heinz_, Mar 19 2012 %t A182714 z = 60; f[n_] := f[n] = IntegerPartitions[n]; t1 = Table[Count[f[n], p_ /; Count[p, 1] < Count[p, 3]], {n, 0, z}] (* _Clark Kimberling_, Apr 01 2014 *) %t A182714 b[n_, i_] := b[n, i] = Module[{g, h}, If[n==0, {1, 0}, If[i<2, {0, 0}, g = b[n, i-1]; h = If[i>n, {0, 0}, b[n-i, i]]; {g[[1]] + h[[1]], g[[2]] + h[[2]] + If[i==4, h[[1]], 0]}]]]; a[n_] := b[n, n][[2]]; Table[a[n], {n, 1, 70}] (* _Jean-François Alcover_, Sep 21 2015, after _Alois P. Heinz_ *) %t A182714 Table[Count[Flatten@Cases[IntegerPartitions[n], x_ /; Last[x] != 1], 4], {n, 52}] (* _Robert Price_, May 15 2020 *) %o A182714 (Sage) A182714 = lambda n: sum(list(p).count(4) for p in Partitions(n) if 1 not in p) %Y A182714 Column 4 of A194812. %Y A182714 Cf. A015739, A024788, A135010, A138121, A182703, A182712, A182713, A240058. %K A182714 nonn %O A182714 1,8 %A A182714 _Omar E. Pol_, Nov 13 2011