A192283 Sum of prime anti-divisors of n = sum of prime anti-divisors of n+1 with n > 1.

237, 4019, 7401, 14178, 14339, 18435, 19146, 21405, 54562, 56348, 60125, 82967, 98447, 99347, 109157, 113391, 125333, 132096, 132386, 145063, 173399, 195213, 260288, 278271, 343848, 384169, 396813, 434375, 460758, 474105, 477707, 528845, 550400, 587211

Offset

1,1

Comments

Like A006145 but using anti-divisors.

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Example

Anti-divisors of 7401 are 2, 6, 19, 41, 113, 131, 361, 779, 4934. The primes are 2, 19, 41, 113 and 131 whose sum is 306.
Anti-divisors of 7402 are 3, 4, 5, 7, 9, 15, 21, 35, 45, 47, 63, 105, 113, 131, 141, 235, 315, 329, 423, 705, 987, 1645, 2115, 2961, 4935. The primes are 3, 5, 7, 47, 113 and 131 whose sum is 306.

Maple

with(numtheory);
P:=proc(n)
local a, b, i, k;
b:=2;
for i from 4 to n do
  a:=0;
  for k from 2 to i-1 do
    if abs((i mod k)- k/2) < 1 then if isprime(k) then a:=a+k; fi; fi;
  od;
  if a=b then print(i-1); fi;
  b:=a;
od;
end:
P(200000);

Crossrefs

Cf. A002961, A006145, A066272, A192282

Sequence in context: A255618 A237592 A256805 * A069420 A205068 A229077

Adjacent sequences: A192280 A192281 A192282 * A192284 A192285 A192286

Keyword

nonn

Author

Paolo P. Lava, Jul 27 2011

Status

approved