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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
OFFSET
1,1
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
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(16)-a(52) from Jon E. Schoenfield, Aug 19 2018
STATUS
approved