login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A076274 2p-1 where p is 1 or a prime. 29
1, 3, 5, 9, 13, 21, 25, 33, 37, 45, 57, 61, 73, 81, 85, 93, 105, 117, 121, 133, 141, 145, 157, 165, 177, 193, 201, 205, 213, 217, 225, 253, 261, 273, 277, 297, 301, 313, 325, 333, 345, 357, 361, 381, 385, 393, 397, 421, 445, 453, 457, 465, 477, 481, 501, 513, 525, 537, 541 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
A076271(a(n)) = A008578(n)^2 for all n.
a(n+1) - a(n) = 2*A075526(n) for all n.
G.f.: 1 + Sum_{ j>=1 } Sum_{ k>=1 } x^(pi(k/2)+j), where pi(k) is the prime counting function. - Benedict W. J. Irwin, Jun 13 2016
a(n) = 2*A008578(n) - 1. - Alois P. Heinz, Nov 28 2023
MATHEMATICA
Join[{1}, 2*Prime[Range[100]]-1] (* Harvey P. Dale, Nov 29 2015 *)
PROG
(PARI) a(n)=if(n>1, 2*prime(n-1)-1, 1) \\ Charles R Greathouse IV, Apr 29 2015
(Magma) [2*NthPrime(n-1)-1: n in [1..60]]; // Vincenzo Librandi, Jul 31 2017
CROSSREFS
Positions of squares in A076271.
Subsequence of A186621 and of A005408.
Sequence in context: A007042 A178415 A249424 * A058989 A049691 A206297
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Oct 04 2002
EXTENSIONS
New definition from Thomas Baruchel, Oct 21 2003
Offset changed from Vincenzo Librandi, Jul 31 2017
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 16 21:54 EDT 2024. Contains 371755 sequences. (Running on oeis4.)