A238714 Final divisor of A238529(n).

2, 3, 4, 5, 5, 7, 2, 3, 3, 11, 5, 13, 5, 7, 8, 17, 2, 19, 2, 10, 3, 23, 5, 5, 11, 9, 5, 29, 10, 31, 2, 5, 7, 11, 5, 37, 17, 7, 7, 41, 5, 43, 5, 11, 10, 47, 4, 7, 2, 11, 17, 53, 3, 7, 4, 13, 9, 59, 12, 61, 29, 11, 4, 11, 2, 67, 5, 17, 14, 71, 12, 73, 11, 3, 7, 5, 5

Offset

2,1

Comments

Conjecture: Every integer greater than 1, except 6, is an element of the sequence.

Links

Tom Davis, Table of n, a(n) for n = 2..10001

Example

a(8) = 2, because 8 mod sopfr(8) = 8 mod 6 = 2, and 2 mod sopfr(2) = 2 mod 2 = 0, and 2 is the last divisor used.
a(21) = 10, because 21 mod sopfr(21) = 21 mod 10 = 1, and 10 is the last divisor used.

Prog

(Python)
def primfacs(n):
   i = 2
   primfac = []
   while i * i <= n:
       while n % i == 0:
           primfac.append(i)
           n //= i
       i += 1
   if n > 1:
       primfac.append(n)
   return primfac
def sopfr(n):
   plist = primfacs(n)
   l = len(plist)
   s = 0
   while l > 0:
       s += plist[l - 1]
       l -= 1
   return s
n = 2
max = 1000
lst = []
while n <= max:
   rem = n
   while rem > 1:
       last = sopfr(rem)
       rem = rem % last
   lst.append(last)
   n += 1
print(lst)

Crossrefs

Cf. A238529.

Sequence in context: A017855 A051598 A086993 * A289311 A351926 A345303

Adjacent sequences: A238711 A238712 A238713 * A238715 A238716 A238717

Keyword

nonn

Author

J. Stauduhar, Mar 03 2014

Status

approved