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A084181 2^n+(-2)^n-(-1)^n. 1
1, 1, 7, 1, 31, 1, 127, 1, 511, 1, 2047, 1, 8191, 1, 32767, 1, 131071, 1, 524287, 1, 2097151, 1, 8388607, 1, 33554431, 1, 134217727, 1, 536870911, 1, 2147483647, 1, 8589934591, 1, 34359738367, 1, 137438953471, 1, 549755813887, 1, 2199023255551 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Binomial transform is A084182.
LINKS
FORMULA
a(n)=2^n+(-2)^n-(-1)^n;
G.f.: (1+2x+4x^2)/((1+x)(1+2x)(1-2x));
E.g.f.: exp(2x)-exp(-x)+exp(-2x).
MATHEMATICA
LinearRecurrence[{-1, 4, 4}, {1, 1, 7}, 50] (* or *) Riffle[ LinearRecurrence[ {5, -4}, {1, 7}, 30], 1] (* Harvey P. Dale, Jan 02 2019 *)
CROSSREFS
Cf. A083420.
Sequence in context: A083994 A301731 A228498 * A002678 A147482 A171770
KEYWORD
easy,nonn
AUTHOR
Paul Barry, May 19 2003
STATUS
approved

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Last modified March 29 03:51 EDT 2024. Contains 371264 sequences. (Running on oeis4.)