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

 

Logo

Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A105090 Sum of the left diagonal in ordered 3 X 3 prime squares. 0
36, 133, 253, 389, 533, 679, 841, 1007, 1175, 1327, 1489, 1703, 1859, 2021, 2209, 2405, 2571, 2769, 2977, 3139, 3319, 3545, 3733, 3905, 4135, 4361, 4525, 4721, 4891, 5099, 5319, 5549, 5743, 5987, 6177, 6361, 6599, 6813, 7021, 7193, 7425, 7675, 7927 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..43.

FORMULA

An ordered 3 X 3 prime square is 9 consecutive primes arranged in a square of the form p(9n-8) p(9n-7) p(9n-6) p(9n-5) p(9n-4) p(9n-3) p(9n-2) p(9n-1) p(9n) n=1, 2, .. Left diagonal is p(9n-8) p(9n-4) p(9n)

EXAMPLE

The first 3 X 3 prime square

2 3 5

7 11 13

17 19 23

sum of left diagonal = 2 + 11 + 23 = 36 the first entry.

PROG

(PARI) sum3x3left(n) = { local(x, j, s); forstep(x=0, n, 9, s=0; forstep(j=1, 9, 4, s += prime(x+j); ); print1(s", ") ) }

CROSSREFS

Sequence in context: A260130 A155708 A196891 * A254284 A076578 A044368

Adjacent sequences:  A105087 A105088 A105089 * A105091 A105092 A105093

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard, Apr 07 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 December 13 09:18 EST 2018. Contains 318086 sequences. (Running on oeis4.)