login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A048851 Length of hypotenuse squared in right triangle formed by a prime spiral plotted in Cartesian coordinates. 3
8, 13, 34, 74, 170, 290, 458, 650, 890, 1370, 1802, 2330, 3050, 3530, 4058, 5018, 6290, 7202, 8210, 9530, 10370, 11570, 13130, 14810, 17330, 19610, 20810, 22058, 23330, 24650, 28898, 33290, 35930, 38090, 41522, 45002, 47450, 51218, 54458 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

H. E. Huntley, The Divine Proportion, A Study in Mathematical Beauty. New York: Dover, 1970. See Chapter 13, Spira Mirabilis, especially Fig. 13-5, page 173.

LINKS

Table of n, a(n) for n=1..39.

FORMULA

To begin prime spiral, plot (2, 0), (0, 2). Square of hypotenuse is c^2 = a^2 + b^2, or 8 = 4 + 4, so a(1) = 8.

a(n) = A000040(n-1)^2 + A000040(n)^2, n >= 2. - Mamuka Jibladze, Mar 24 2017

EXAMPLE

a(2) = 13 because c^2 = a^2 + b^2 = 4 + 9 = 13.

CROSSREFS

Cf. A006094.

Sequence in context: A096371 A063585 A258768 * A039298 A218627 A279711

Adjacent sequences:  A048848 A048849 A048850 * A048852 A048853 A048854

KEYWORD

easy,nonn

AUTHOR

Enoch Haga

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 September 17 01:53 EDT 2021. Contains 347478 sequences. (Running on oeis4.)