A024947 - OEIS

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A024947

a(n) = Sum_{i=1..floor((n+2)/4)} a(2i-1)*a(n-2i+1), with a(1)=a(2)=1 and a(3)=3.

1, 1, 3, 3, 3, 12, 21, 30, 66, 138, 264, 525, 1029, 2460, 5079, 10344, 22197, 50421, 108966, 229827, 498432, 1136190, 2495118, 5390319, 11879355, 27012990, 60008826, 131877372, 292070991, 670433502, 1500384540, 3327218859, 7449719727, 17089051899

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Table of n, a(n) for n=1..34.

CROSSREFS

Sequence in context: A152575 A170851 A052900 * A291407 A378153 A147823

Adjacent sequences: A024944 A024945 A024946 * A024948 A024949 A024950

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Offset corrected and title improved by Sean A. Irvine, Jul 30 2019

STATUS

approved