A081053 Sum of a prime and the square of a prime.
6, 7, 9, 11, 12, 14, 15, 16, 17, 20, 21, 22, 23, 26, 27, 28, 30, 32, 33, 35, 36, 38, 40, 41, 42, 44, 45, 46, 47, 48, 50, 51, 52, 54, 56, 57, 60, 62, 63, 65, 66, 68, 70, 71, 72, 75, 76, 77, 78, 80, 82, 83, 84, 86, 87, 88, 90, 92, 93, 96, 98, 101, 102, 104, 105, 106, 107, 108
Offset: 1
Keywords
Examples
7=2^2+3
Links
- Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
Programs
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Maple
G := proc(n::posint) local p,q; p := 2; while p<=n-2 do q := n-p^2; if type(q,posint) then if isprime(q) then return(true,p,q); end if; end if; p := nextprime(p); end do; return(false); end:
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Mathematica
Take[ Union[ Flatten[ Table[ Prime[i] + Prime[j]^2, {i, 1, 30}, {j, 1, 5}]]], 70] -
PARI
is(n)=if(n%2, isprime(n-4) || isprimepower(n-2)==2, forprime(q=3, sqrtint(n), if(isprime(n-q^2), return(1))); n==6) \\ Charles R Greathouse IV, Nov 01 2017
Formula
a(n) = p^2 + q, p and q primes.
Extensions
More terms from Robert G. Wilson v, Mar 05 2003
Comments