login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A273284
A273282(n)^Omega(n), where Omega = A001222.
5
2, 3, 4, 5, 4, 7, 8, 9, 9, 11, 8, 13, 9, 9, 16, 17, 8, 19, 8, 9, 9, 23, 16, 25, 25, 27, 27, 29, 27, 31, 32, 25, 25, 25, 16, 37, 25, 25, 16, 41, 27, 43, 27, 27, 25, 47, 32, 49, 27, 49, 27, 53, 16, 49, 16, 49, 49, 59, 16, 61, 49, 27, 64, 49, 27, 67, 27, 49, 27, 71, 32, 73, 49
OFFSET
2,1
COMMENTS
a(n) <= A079867(n) for any n>=2.
a(n) = n iff n is the power of a prime (A246655).
LINKS
FORMULA
a(n) = A273282(n)^A001222(n).
EXAMPLE
a(33) = 25 because Omega(33)=2 and 5^2 < 33 < 7^2.
If n= 3^3 * 31^2 * 67 then a(n)= 7^6 and A273285(n)=11^6 because Omega(n)=6 and 7^6 < n < 11^6.
MATHEMATICA
Table[NextPrime[(Floor[n^(1/PrimeOmega[n])] + 1) , -1]^PrimeOmega[n], {n, 2, 50}] (* G. C. Greubel, May 26 2016 *)
PROG
(Sage) s=sloane.A001222; [previous_prime(floor(n^(1/s(n)))+1)^s(n) for n in (2..74)]
(PARI) a(n) = my(bn=bigomega(n)); precprime(sqrtnint(n, bn))^bn; \\ Michel Marcus, May 24 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Giuseppe Coppoletta, May 20 2016
STATUS
approved