A001404 - OEIS

A001404

Triangle of values of 2-d recurrence.

1, 1, 1, 2, 2, 1, 4, 5, 2, 1, 9, 11, 5, 2, 1, 20, 25, 12, 5, 2, 1, 45, 57, 27, 12, 5, 2, 1, 102, 129, 62, 28, 12, 5, 2, 1, 231, 293, 141, 64, 28, 12, 5, 2, 1, 524, 665, 321, 146, 65, 28, 12, 5, 2, 1, 1189, 1510, 729, 333, 148, 65, 28, 12, 5, 2, 1, 2699, 3428, 1656

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OFFSET

0,4

COMMENTS

The first column of the triangle (see example) appears to be A167750. [Joerg Arndt, Jul 09 2012]

LINKS

Table of n, a(n) for n=0..68.

EXAMPLE

Triangle starts

1, 1,

2, 2, 1,

4, 5, 2, 1,

9, 11, 5, 2, 1,

20, 25, 12, 5, 2, 1,

45, 57, 27, 12, 5, 2, 1,

102, 129, 62, 28, 12, 5, 2, 1,

231, 293, 141, 64, 28, 12, 5, 2, 1,

524, 665, 321, 146, 65, 28, 12, 5, 2, 1,

1189, 1510, 729, 333, 148, 65, 28, 12, 5, 2, 1,

MAPLE

a[ 0, 0 ] := 1; for i from 1 to N do a[ i, 0 ] := a[ i-1, 0 ]+a[ i-1, 1 ]; for j from 1 to i do a[ i, j ] := sum(a[ i-j, t ], t=0..min(j+1, N)) od; od;

PROG

(PARI) T(m, n)=if(m<n, 0, if(m==0&&n==0, 1, if(n==0, T(m-1, 0)+T(m-1, 1), sum(t=0, n+1, T(m-n, t))))) /* Ralf Stephan */

CROSSREFS

Cf. A001410.

Sequence in context: A341146 A355276 A272888 * A104580 A202193 A105306

Adjacent sequences: A001401 A001402 A001403 * A001405 A001406 A001407

KEYWORD

tabl,nonn,easy

AUTHOR

N. J. A. Sloane [ I have temporarily mislaid the name of the person who sent this ]

EXTENSIONS

Sequence corrected by Sean A. Irvine, Jul 08 2012

STATUS

approved