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A158841 Triangle read by rows, matrix product of A145677 * A004736. 2
1, 3, 1, 7, 4, 2, 13, 9, 6, 3, 21, 16, 12, 8, 4, 31, 25, 20, 15, 10, 5, 43, 36, 30, 24, 18, 12, 6, 57, 49, 42, 35, 28, 21, 14, 7, 73, 64, 56, 48, 40, 32, 24, 16, 8, 91, 81, 72, 63, 54, 45, 36, 27, 18, 9 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..55.

FORMULA

T(n,k) = Sum_{j=k..n} A145677(n-1,j-1)*A004736(j,k), assuming column enumeration k >= 1 in A004736. - R. J. Mathar, Nov 05 2011

EXAMPLE

First few rows of the triangle:

    1;

    3,   1;

    7,   4,   2;

   13,   9,   6,   3;

   21,  16,  12,   8,   4;

   31,  25,  20,  15,  10,  5;

   43,  36,  30,  24,  18, 12,  6;

   57,  49,  42,  35,  28, 21, 14,  7;

   73,  64,  56,  48,  40, 32, 24, 16,  8;

   91,  81,  72,  63,  54, 45, 36, 27, 18,  9;

  111, 100,  90,  80,  70, 60, 50, 40, 30, 20, 10;

  133, 121, 110,  99,  88, 77, 66, 55, 44, 33, 22, 11;

  157, 144, 132, 120, 108, 96, 84, 72, 60, 48, 36, 24, 12;

  ...

MAPLE

A145677 := proc(n, k)

        if n <0 or k < 0 or k > n then

                0;

        elif k = 0 then

                1;

        elif k = n then

                n ;

        else

                0 ;

        end if;

end proc:

A004736 := proc(n, k)

        if n <0 or k < 1 or k > n then

                0;

        else

                n-k+1 ;

        end if;

end proc:

A158841 := proc(n, k)

        add( A145677(n-1, j-1)*A004736(j, k), j=k..n) ;

end proc: # R. J. Mathar, Nov 05 2011

CROSSREFS

Cf. A145677, A002061 (column k=1), A158842 (row sums).

Sequence in context: A286513 A193970 A274510 * A213576 A021319 A190177

Adjacent sequences:  A158838 A158839 A158840 * A158842 A158843 A158844

KEYWORD

nonn,tabl,easy

AUTHOR

Gary W. Adamson and Roger L. Bagula, Mar 28 2009

STATUS

approved

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Last modified January 19 00:40 EST 2020. Contains 331030 sequences. (Running on oeis4.)