login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A168385 Numbers of the form |a^b - c^d| where a, b, c and d are the first 4 primes. 3
3, 76, 115, 194, 311, 318, 2155, 2162, 16798, 16799, 78116, 78117 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are 4! = 24 permutations of 4 elements, because of commutativity of |x|=|- x| sequence has 4!/2 = 12 different terms.

Note that two terms of sequence (3 and 311) are prime numbers.

REFERENCES

Ivan Niven und H. S. Zuckermann, Einfuehrung in die Zahlentheorie, B.I. Mannheim 1976

Friedhelm Padberg, Elementare Zahlentheorie, Spektrum Akademischer Verlag, 2. Auflage 1991

LINKS

Table of n, a(n) for n=1..12.

EXAMPLE

(1) 3 = 2^7 - 5^3 = prime(2)

(2) 76 = 2 ^ 2 x 19 = 5^3 - 7^2

(3) 115 = 5 x 23 = 3^5 - 2^7

(4) 194 = 2 x 97 = 3^5 - 7^2

(5) 311 = 7^3 - 2^5 = prime(2^6)

(6) 318 = 2 x 3 x 53 = 7^3 - 5^2

(7) 2155 = 5 x 431 = 3^7 - 2^5

(8) 2162 = 2 x 23 x 47 = 3^7 - 5^2

(9) 16798 = 2 x 37 x 227 = 7^5 - 3^2

(10) 16799 = 107 x 157 = 7^5 - 2^3

(11) 78116 = 2 ^ 2 x 59 x 331 = 5^7 - 3^2

(12) 78117 = 3 x 13 x 2003 = 5^7 - 2^3

CROSSREFS

Cf. A168349.

Sequence in context: A308866 A089301 A037110 * A042267 A201428 A141103

Adjacent sequences:  A168382 A168383 A168384 * A168386 A168387 A168388

KEYWORD

fini,full,nonn

AUTHOR

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 24 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 17 06:12 EST 2022. Contains 350378 sequences. (Running on oeis4.)