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Search: id:A107767
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A107767 Related to the conformational properties of alkanes. +0
1
0, 1, 4, 16, 52, 169, 520, 1600, 4840, 14641, 44044, 132496, 397852, 1194649, 3585040, 10758400, 32278480, 96845281, 290545684, 871666576, 2615029252, 7845176329, 23535617560, 70607118400, 211821620920, 635465659921 (list; graph; listen)
OFFSET

1,3

REFERENCES

Gy. Tasi and F. Mizukami, Quantum algebraic-combinatoric study of the conformational properties of n-alkanes, J. Math. Chemistry, 25, 1999, 55-64 (see p. 60).

FORMULA

a(n)=(1+3^n-2*3^(n/2))/4 if n even; a(n)=(1+3^n-4*3^((n-1)/2))/4 if n odd.

MAPLE

a:=proc(n) if n mod 2 = 0 then (1+3^n-2*3^(n/2))/4 else (1+3^n-4*3^((n-1)/2))/4 fi end: seq(a(n), n=1..32);

CROSSREFS

Sequence in context: A058234 A007688 A100774 this_sequence A087972 A074409 A056589

Adjacent sequences: A107764 A107765 A107766 this_sequence A107768 A107769 A107770

KEYWORD

nonn

AUTHOR

Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 12 2005

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Last modified December 2 15:58 EST 2008. Contains 150992 sequences.


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