login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A318157 Primes that are one more or one less than the sum of four consecutive composite numbers. 1
101, 103, 107, 137, 139, 197, 199, 223, 227, 257, 307, 347, 367, 373, 379, 461, 463, 467, 479, 487, 491, 499, 569, 571, 577, 587, 613, 617, 619, 641, 643, 677, 683, 701, 733, 739, 743, 751, 809, 811, 821, 823, 827, 829, 853, 857, 859, 863, 877, 881, 883, 941 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000

EXAMPLE

24 + 25 + 26 + 27 - 1 = 101;

24 + 25 + 26 + 27 + 1 = 103;

25 + 26 + 27 + 28 + 1 = 107.

26 + 27 + 28 + 29 - 1 = 109, but 29 is not composite, so 109 is not in the sequence.

MATHEMATICA

tempList = Table[(Plus@@Range[n, n + 3]) * KroneckerDelta[PrimePi[n - 1], PrimePi[n + 3]], {n, 250}]; Union[Select[tempList - 1, PrimeQ], Select[tempList + 1, PrimeQ]] (* Alonso del Arte, Sep 02 2018 *)

PROG

(Python)

from sympy import isprime

A318157_list = []

for n in range(2, 10**6):

    if not (isprime(n) or isprime(n+1) or isprime(n+2) or isprime(n+3)):

        if isprime(4*n+5):

            A318157_list.append(4*n+5)

        if isprime(4*n+7):

            A318157_list.append(4*n+7) # Chai Wah Wu, Jan 02 2019

CROSSREFS

Cf. A296012.

Sequence in context: A329737 A166571 A201965 * A117837 A176929 A330563

Adjacent sequences:  A318154 A318155 A318156 * A318158 A318159 A318160

KEYWORD

nonn

AUTHOR

Martin Michael Musatov, Aug 19 2018

EXTENSIONS

a(16)-a(52) from Jon E. Schoenfield, Aug 19 2018

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 August 14 04:13 EDT 2020. Contains 336477 sequences. (Running on oeis4.)