|
|
|
|
1, 1, 1, 3, 5, 3, 1, 3, 11, 7, 15, 3, 5, 21, 23, 13, 29, 15, 33, 35, 3, 39, 41, 11, 3, 5, 51, 53, 3, 7, 21, 65, 17, 69, 37, 15, 39, 3, 83, 43, 89, 15, 95, 3, 7, 33, 105, 111, 113, 57, 29, 119, 15, 5, 1, 131, 67, 15, 69, 35, 141, 73, 51, 155, 39, 79, 165, 21, 173, 87, 11, 179
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,4
|
|
LINKS
|
|
|
FORMULA
|
a(n) = Product_{odd primes p dividing prime(n)-1} p.
|
|
EXAMPLE
|
|
|
MATHEMATICA
|
Array[#/2^IntegerExponent[#, 2] &[Times @@ FactorInteger[Prime[#] - 1][[All, 1]]] &, 72] (* Michael De Vlieger, Aug 09 2022 *)
|
|
PROG
|
(PARI) a(n) = factorback(setminus(factorint(prime(n)-1)[, 1]~, [2]))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|