login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A054755 Odd powers of primes of form q=x^2+1 (A002496). 1
2, 5, 8, 17, 32, 37, 101, 125, 128, 197, 257, 401, 512, 577, 677, 1297, 1601, 2048, 2917, 3125, 3137, 4357, 4913, 5477, 7057, 8101, 8192, 8837, 12101, 13457, 14401, 15377, 15877, 16901, 17957, 21317, 22501, 24337, 25601, 28901, 30977, 32401 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A002496 is a subset, the odd power exponent is 1.

LINKS

Table of n, a(n) for n=1..42.

FORMULA

EulerPhi[a(n)]=[q^(2k)]*(q-1) and a(n)-EulerPhi[a(n)]=q^(2k), where q=1+x^2 and prime.

EXAMPLE

a(20) = 3125 = 5^5, q = 5 = 4^2+1 and Phi[3125] = 2500 = 50^2, 3125-Phi[3125] = 625 = 25x25.

CROSSREFS

Cf. A000010, A051953, A002496, A039770.

Sequence in context: A034445 A259580 A054754 * A093331 A162216 A032158

Adjacent sequences:  A054752 A054753 A054754 * A054756 A054757 A054758

KEYWORD

nonn

AUTHOR

Labos Elemer, Apr 25 2000

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 6 08:53 EST 2016. Contains 278775 sequences.