cp's OEIS Frontend

A014462 Triangular array formed from elements to left of middle of Pascal's triangle.

%I A014462 #44 Jul 02 2025 16:01:55
%S A014462 1,1,1,3,1,4,1,5,10,1,6,15,1,7,21,35,1,8,28,56,1,9,36,84,126,1,10,45,
%T A014462 120,210,1,11,55,165,330,462,1,12,66,220,495,792,1,13,78,286,715,1287,
%U A014462 1716,1,14,91,364,1001,2002,3003,1,15,105,455,1365,3003,5005,6435,1,16
%N A014462 Triangular array formed from elements to left of middle of Pascal's triangle.
%C A014462 Coefficients for Pontryagin classes of projective spaces. See p. 3 of the Wilson link. Aerated to become a lower triangular matrix with alternating zeros on the diagonal, this matrix appparently becomes the reverse, or mirror, of A117178. - _Tom Copeland_, May 30 2017
%H A014462 Reinhard Zumkeller, <a href="/A014462/b014462.txt">Rows n = 1..200 of triangle, flattened</a>
%H A014462 Jon Maiga, <a href="http://sequencedb.net/s/A014462">Computer-generated formulas for A014462</a>, Sequence Machine.
%H A014462 D. Wilson, <a href="http://math.uchicago.edu/~chicagotopology2/cobordism-and-k-theory-talk.pdf">Genera: From cobordism to K-theory</a>, Jul 2016.
%H A014462 <a href="/index/Pas#Pascal">Index entries for triangles and arrays related to Pascal's triangle</a>
%e A014462 Array begins:
%e A014462   1;
%e A014462   1;
%e A014462   1,  3;
%e A014462   1,  4;
%e A014462   1,  5, 10;
%e A014462   1,  6, 15;
%e A014462   1,  7, 21,  35;
%e A014462   1,  8, 28,  56;
%e A014462   1,  9, 36,  84, 126;
%e A014462   1, 10, 45, 120, 210;
%e A014462   1, 11, 55, 165, 330, 462;
%o A014462 (Haskell)
%o A014462 a014462 n k = a014462_tabf !! (n-1) !! (k-1)
%o A014462 a014462_row n = a014462_tabf !! (n-1)
%o A014462 a014462_tabf = map reverse a014413_tabf
%o A014462 -- _Reinhard Zumkeller_, Dec 24 2015
%Y A014462 Cf. A014413, A034868, A058622 (row sums).
%Y A014462 Cf. A001791 (a half-diagonal and diagonal sums).
%Y A014462 Cf. A007318, A000037, A008314.
%Y A014462 Cf. A117178.
%K A014462 tabf,nonn,easy
%O A014462 1,4
%A A014462 _Mohammad K. Azarian_
%E A014462 More terms from _James Sellers_