OFFSET
1,1
LINKS
Dumitru Damian, Table of n, a(n) for n = 1..10456
EXAMPLE
For k=11151 we have 11150 = 2 * 5^2 * 223 which is composite with four prime factors, 11151 = 3^3 * 7 * 59 which is composite with five prime factors and 11152 = 2^4 * 17 * 41 which is composite with six prime factors.
MATHEMATICA
SequencePosition[PrimeOmega[Range[100000]], {4, 5, 6}][[;; , 1]]+1 (* Harvey P. Dale, Jul 30 2024 *)
PROG
(Sage)
# The following SageMath algorithm will generate all terms up to 100000
L=[]
for n in [1..100000]:
sum1, sum2, sum3 = 0, 0, 0
for f in list(factor(n)):
sum1+=f[1]
for f in list(factor(n+1)):
sum2+=f[1]
for f in list(factor(n+2)):
sum3+=f[1]
if sum1==4 and sum2==5:
if sum3==6:
L.append(n+1)
print(L)
(PARI) for(n=3, 100000, if(bigomega(n-1)==4&&bigomega(n)==5&&bigomega(n+1)==6, print1(n, ", "))) \\ Hugo Pfoertner, Mar 07 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Sean Lestrange, Mar 07 2021
STATUS
approved