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A238377 Row sums of triangle in A204028. 2
1, 2, 6, 10, 17, 24, 34, 44, 57, 70, 86, 102, 121, 140, 162, 184, 209, 234, 262, 290, 321, 352, 386, 420, 457, 494, 534, 574, 617, 660, 706, 752, 801, 850, 902, 954, 1009, 1064, 1122, 1180 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..39.

Index entries for linear recurrences with constant coefficients, signature (2,0,-2,1).

FORMULA

G.f.: (1+2*x^2)/((1+x)*(1-x)^3)).

a(2*n) = A056109(n).

a(2*n+1) = A049450(n+1) = 2*A000326(n+1).

a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4), a(0) = 1, a(1) = 2, a(2) = 6, a(3) = 10.

EXAMPLE

Triangle in A204028 begins:

1;............................sum = 1

1, 1;.........................sum = 2

1, 4, 1;......................sum = 6

1, 4, 4, 1;...................sum = 10

1, 4, 7, 4, 1;................sum = 17

1, 4, 7, 7, 4, 1;.............sum = 24

1, 4, 7, 10, 7, 4, 1;.........sum = 34

1, 4, 7, 10, 10, 7, 4, 1;.....sum = 44

CROSSREFS

Cf. A056109, A049450, A204028.

Sequence in context: A100899 A099540 A190695 * A180739 A274679 A229218

Adjacent sequences:  A238374 A238375 A238376 * A238378 A238379 A238380

KEYWORD

easy,nonn

AUTHOR

Philippe Deléham, Feb 25 2014

EXTENSIONS

Corrected by R. J. Mathar, Aug 08 2015

STATUS

approved

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Last modified January 27 04:57 EST 2020. Contains 331291 sequences. (Running on oeis4.)