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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A101947 A101909 sorted and duplicates removed. 4
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

PROG

(PARI) bet2n4n(n) = { local(c, c1, x, y); a=vector(5001); for(x=1, n, c=0; forprime(y=2*x+1, 4*x-1, c++; ); a[x] = c; ); b=vecsort(a); for(x=1, 5000, if(b[x]>0, if(b[x]<>b[x+1], print1(b[x]", ") ) ); ) }

(PARI) s=0; v=vectorsmall(10^6, n, s+=isprime(4*n-1)+isprime(4*n-3)-isprime(2*n-1)); v=vecsort(v, , 8); vecextract(v, Str("1..", #v\2)) \\ Charles R Greathouse IV, Mar 12 2012

CROSSREFS

Cf. A101909, A101983-A101985.

Sequence in context: A194845 A194056 A020753 * A183223 A167520 A051882

Adjacent sequences:  A101944 A101945 A101946 * A101948 A101949 A101950

KEYWORD

easy,nonn

AUTHOR

Cino Hilliard, Jan 28 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 12 16:50 EST 2018. Contains 317116 sequences. (Running on oeis4.)