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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A106588 Difference between n-th prime squared and n-th perfect square. 1
3, 5, 16, 33, 96, 133, 240, 297, 448, 741, 840, 1225, 1512, 1653, 1984, 2553, 3192, 3397, 4128, 4641, 4888, 5757, 6360, 7345, 8784, 9525, 9880, 10665, 11040, 11869, 15168, 16137, 17680, 18165, 20976, 21505, 23280, 25125, 26368, 28329, 30360 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) is itself prime for a(1) = 3, a(2) = 5, ... a(n) is itself a perfect square for a(3) = 16 = 2^4, a(12) = 1225 = 5^2 * 7^2, .... a(n) is a semiprime for a(4) = 33 = 3 * 11, a(6) = 133 = 7 * 19, a(18) = 3397 = 43 * 79, ... - Jonathan Vos Post, May 14 2005

LINKS

Table of n, a(n) for n=1..41.

EXAMPLE

a(5)=96 because 121 (fifth prime^2) - 25 (fifth square) = 96.

MATHEMATICA

Table[Prime[n]^2 - n^2, {n, 50}]

CROSSREFS

Cf. A014688, A076368, A075526, A001248, A000290.

Sequence in context: A019096 A295358 A077551 * A123785 A121646 A226205

Adjacent sequences:  A106585 A106586 A106587 * A106589 A106590 A106591

KEYWORD

easy,nonn

AUTHOR

Alexandre Wajnberg, May 10 2005

EXTENSIONS

Extended by Ray Chandler, May 13 2005

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 09:11 EDT 2019. Contains 327128 sequences. (Running on oeis4.)