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

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A131991 a(n) = 1 + prime(n) + prime(n)^2 + prime(n)^3. 8
15, 40, 156, 400, 1464, 2380, 5220, 7240, 12720, 25260, 30784, 52060, 70644, 81400, 106080, 151740, 208920, 230764, 305320, 363024, 394420, 499360, 578760, 712980, 922180, 1040604, 1103440, 1236600, 1307020, 1455780, 2064640, 2265384 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = 1 + A060800(n)*A000040(n).

a(n) = (A030514(n) - 1)/A006093(n).

a(n) = A000203(A000040(n)^3). - Zak Seidov, Feb 13 2016

EXAMPLE

a(4)=400 because the 4th prime is 7, 7^3=343, 7^2=49, and 343+49+7+1=400.

MAPLE

A131991:= n -> map (p -> p^(3)+p^(2)+p+1, ithprime(n)):

seq (A131991(n), n=1..32); # Jani Melik, Jan 25 2011

MATHEMATICA

#^3 + #^2 + # + 1 &/@Prime[Range[100]] (* Vincenzo Librandi, Mar 20 2014 *)

PROG

(MAGMA) [1+NthPrime(n)+NthPrime(n)^2+NthPrime(n)^3: n in [1..40]]; // Vincenzo Librandi, Dec 27 2010

CROSSREFS

Cf. A030078, A008864, A131992, A131993.

Cf. A000040, A000203. - Zak Seidov, Feb 13 2016

Sequence in context: A175926 A038991 A068020 * A116042 A219378 A280045

Adjacent sequences:  A131988 A131989 A131990 * A131992 A131993 A131994

KEYWORD

nonn,easy

AUTHOR

Reinhard Zumkeller, Aug 06 2007

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 20 08:12 EST 2017. Contains 294962 sequences.