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 A152146 #24 Feb 28 2024 11:44:05 %S A152146 1,0,1,0,1,1,0,2,1,1,0,2,2,1,1,0,3,3,2,1,1,0,3,5,3,2,1,1,0,4,6,5,3,2, %T A152146 1,1,0,4,9,7,5,3,2,1,1,0,5,11,11,7,5,3,2,1,1,0,5,15,14,11,7,5,3,2,1,1, %U A152146 0,6,18,20,15,11,7,5,3,2,1,1,0,6,23,26,22,15,11,7,5,3,2,1,1 %N A152146 Triangle read by rows: T(n,k) (n >= 0, 0 <= k <= n) = number of partitions of 2n into 2k odd parts. %C A152146 In both this and A152157, reading columns downwards "converges" to A000041. %C A152146 Also the number of strict integer partitions of 2n with alternating sum 2k. Also the number of normal integer partitions of 2n of which 2k parts are odd, where a partition is normal if it covers an initial interval of positive integers. - _Gus Wiseman_, Jun 20 2021 %H A152146 Alois P. Heinz, <a href="/A152146/b152146.txt">Rows n = 0..200, flattened</a> %F A152146 T(n,k) = A152140(2n,2k). %e A152146 Triangle begins: %e A152146 1 %e A152146 0 1 %e A152146 0 1 1 %e A152146 0 2 1 1 %e A152146 0 2 2 1 1 %e A152146 0 3 3 2 1 1 %e A152146 0 3 5 3 2 1 1 %e A152146 0 4 6 5 3 2 1 1 %e A152146 0 4 9 7 5 3 2 1 1 %e A152146 0 5 11 11 7 5 3 2 1 1 %e A152146 0 5 15 14 11 7 5 3 2 1 1 %e A152146 0 6 18 20 15 11 7 5 3 2 1 1 %e A152146 0 6 23 26 22 15 11 7 5 3 2 1 1 %e A152146 0 7 27 35 29 22 15 11 7 5 3 2 1 1 %e A152146 0 7 34 44 40 30 22 15 11 7 5 3 2 1 1 %e A152146 0 8 39 58 52 42 30 22 15 11 7 5 3 2 1 1 %e A152146 0 8 47 71 70 55 42 30 22 15 11 7 5 3 2 1 1 %e A152146 0 9 54 90 89 75 56 42 30 22 15 11 7 5 3 2 1 1 %e A152146 0 9 64 110 116 97 77 56 42 30 22 15 11 7 5 3 2 1 1 %e A152146 0 10 72 136 146 128 100 77 56 42 30 22 15 11 7 5 3 2 1 1 %e A152146 From _Gus Wiseman_, Jun 20 2021: (Start) %e A152146 For example, row n = 6 counts the following partitions (B = 11): %e A152146 (75) (3333) (333111) (33111111) (3111111111) (111111111111) %e A152146 (93) (5331) (531111) (51111111) %e A152146 (B1) (5511) (711111) %e A152146 (7311) %e A152146 (9111) %e A152146 The corresponding strict partitions are: %e A152146 (7,5) (8,4) (9,3) (10,2) (11,1) (12) %e A152146 (6,5,1) (5,4,3) (7,3,2) (9,2,1) %e A152146 (5,4,2,1) (6,4,2) (8,3,1) %e A152146 (7,4,1) %e A152146 (6,3,2,1) %e A152146 The corresponding normal partitions are: %e A152146 43221 33321 3321111 321111111 21111111111 111111111111 %e A152146 322221 332211 32211111 2211111111 %e A152146 2222211 432111 222111111 %e A152146 3222111 %e A152146 22221111 %e A152146 (End) %p A152146 b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0, %p A152146 b(n, i-2)+`if`(i>n, 0, expand(sqrt(x)*b(n-i, i))))) %p A152146 end: %p A152146 T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(2*n, 2*n-1)): %p A152146 seq(T(n), n=0..12); # _Alois P. Heinz_, Jun 21 2021 %t A152146 ats[y_]:=Sum[(-1)^(i-1)*y[[i]],{i,Length[y]}]; %t A152146 Table[Length[Select[IntegerPartitions[n],UnsameQ@@#&&ats[#]==k&]],{n,0,30,2},{k,0,n,2}] (* _Gus Wiseman_, Jun 20 2021 *) %Y A152146 Cf. A035294 (row sums), A107379, A152140, A152157. %Y A152146 Column k = 1 is A004526. %Y A152146 Column k = 2-8 is A026810 - A026816. %Y A152146 The non-strict version is A239830. %Y A152146 The reverse non-strict version is A344610. %Y A152146 The reverse version is A344649 %Y A152146 A000041 counts partitions of 2n with alternating sum 0, ranked by A000290. %Y A152146 A067659 counts strict partitions of odd length. %Y A152146 A103919 counts partitions by sum and alternating sum (reverse: A344612). %Y A152146 A124754 gives alternating sum of standard compositions (reverse: A344618). %Y A152146 A316524 is the alternating sum of the prime indices of n (reverse: A344616). %Y A152146 A344611 counts partitions of 2n with reverse-alternating sum >= 0. %Y A152146 Cf. A006330, A027187, A116406, A120452, A239829, A343941, A344607, A344608, A344609, A344650, A344651, A344739, A344741. %K A152146 nonn,tabl %O A152146 0,8 %A A152146 _R. J. Mathar_, Sep 25 2009, indices corrected Jul 09 2012