

A275749


Prime numbers of the form 2*4^n  27.


4




OFFSET

1,1


COMMENTS

Values of the exponent n are given in A275767, and every exponent (except for the first one) is odd. Consequently, after a(1) = 5, the rightmost digit of each term in this sequence will be 1.
As seen in the link below, a(5) = 2*4^291  27 > 3.1658 * 10^175. As a result of the recent extensions to A275767 by Vincenzo Librandi,
a(6) = 2*4^1263  27 > 5.0442 * 10^760
a(7) = 2*4^2661  27 > 2.4136 * 10^1602
a(8) = 2*4^3165  27 > 6.6206 * 10^1905
a(9) > 2*4^5000  27 > 3.9901 * 10^3010.
These primes a(m) can be used to generate numbers having abundance 26. The formula a(m)*(a(m)+27)/2 produces some of the terms in A275701.


LINKS



FORMULA



EXAMPLE

a(1) = 2*4^A275767(1)  27 = 2*4^2  27 = 32  27 = 5.
a(2) = 2*4^A275767(2)  27 = 2*4^3  27 = 128  27 = 101.
a(3) = 2*4^A275767(3)  27 = 2*4^9  27 = 524288  27 = 524261.
a(4) = 2*4^A275767(4)  27 = 2*4^11  27 = 8388608  27 = 8388581.


MATHEMATICA



CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



