Tetranacci Number
The tetranacci numbers are a generalization of the Fibonacci Numbers defined by 
, 
,
, 
, and the Recurrence Relation
for
. They represent the 
case of the Fibonacci n-Step Number. Thefirst few terms are 1, 1, 2, 4, 8, 15, 29, 56, 108, 208, ... (Sloane's A000078). The ratio of adjacent terms tends to1.92756, which is the Real Root of 
. See also Fibonacci n-Step Number, Fibonacci Number, Tribonacci Number
References
Sloane, N. J. A. SequenceA000078/M1108in ``An On-Line Version of the Encyclopedia of Integer Sequences.''http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S.The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995.
- Type
- Type I Error
- Type II Error
- Ulam Map
- Ulam Number
- Ulam Sequence
- Ulam's Problem
- Ultrametric
- Ultraradical
- Ultraspherical Differential Equation
- Ultraspherical Function
- Ultraspherical Polynomial
- Umbilic Point
- Umbral Calculus
- Umbrella
- Unambiguous
- Unbiased
- Uncia
- Uncorrelated
- Uncountable Set
- Uncountably Infinite Set
- Undecagon
- Undecidable
- Undecillion
- Undetermined Coefficients Method