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A133635
Nonprime numbers k such that binomial(k+p,k) mod k = 1, where p=5.
20
26, 34, 49, 58, 74, 77, 82, 91, 98, 106, 119, 121, 122, 133, 143, 146, 154, 161, 169, 178, 187, 194, 202, 203, 209, 217, 218, 221, 226, 242, 247, 253, 259, 266, 274, 287, 289, 298, 299, 301, 314, 319, 322, 323, 329, 338, 341, 343, 346, 361, 362, 371, 377, 386
OFFSET
1,1
LINKS
MATHEMATICA
nn=400; With[{c=Complement[Range[nn], Prime[Range[PrimePi[nn]]]]}, Select[ c, Mod[Binomial[#+5, #], #]==1&]] (* Harvey P. Dale, Sep 24 2012 *)
PROG
(Python)
from itertools import count, islice
from math import comb
from sympy import isprime
def A133635_gen(startvalue=1): # generator of terms >= startvalue
return filter(lambda k:comb(k+5, k)%k==1 and not isprime(k), count(max(startvalue, 1)))
A133635_list = list(islice(A133635_gen(), 30)) # Chai Wah Wu, Feb 22 2023
KEYWORD
nonn
AUTHOR
Hieronymus Fischer, Sep 30 2007
STATUS
approved