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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A156913 Numbers n with property that A100486(n) is square. 0
2, 4, 6, 11, 14, 21, 37, 75, 81, 176, 194, 310, 324, 332, 345, 399, 447, 612, 1122, 1209, 1614, 1874, 1921, 2186, 2329, 2482, 2509, 2874, 2940, 2975, 3230, 3611, 4185, 4650, 4923, 5172, 5248, 5543, 5587, 5673, 5714, 5764, 6038, 6078, 6250, 6430, 6976, 7023 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For n<2*10^6 there are 411 such numbers.

LINKS

Table of n, a(n) for n=1..48.

FORMULA

pi(n) + n-th prime = square.

EXAMPLE

n=2 pi(2)+p(2)=2+2=4, n=4 pi(4)+p(4)=2+7=9, n=6 pi(6)+p(6)=3+13=16, etc.

PROG

(PARI) isok(n) = issquare(primepi(n) + prime(n)); \\ Michel Marcus, Oct 15 2013

CROSSREFS

Cf. A100486.

Sequence in context: A068059 A108868 A274261 * A238483 A238487 A138461

Adjacent sequences:  A156910 A156911 A156912 * A156914 A156915 A156916

KEYWORD

nonn

AUTHOR

Zak Seidov, Feb 18 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 18 01:20 EST 2018. Contains 317279 sequences. (Running on oeis4.)