A292762 Numbers of the form p^k or 2*p^k, where p is a prime == 3 mod 4 and k is odd.
3, 6, 7, 11, 14, 19, 22, 23, 27, 31, 38, 43, 46, 47, 54, 59, 62, 67, 71, 79, 83, 86, 94, 103, 107, 118, 127, 131, 134, 139, 142, 151, 158, 163, 166, 167, 179, 191, 199, 206, 211, 214, 223, 227, 239, 243, 251, 254, 262, 263, 271, 278, 283, 302, 307, 311, 326, 331, 334, 343, 347, 358, 359, 367, 379, 382
Offset: 1
Keywords
Links
- David A. Corneth, Table of n, a(n) for n = 1..13839 (Terms up to 200000)
Programs
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Mathematica
Do[If[Mod[DivisorSigma[1,n],4]==0 && Mod[EulerPhi[n],4]==2,Print[n]],{n,1,10^3}] (* Vincenzo Librandi, Oct 02 2017 *) -
PARI
isok(m) = ((sigma(m) % 4) == 0) && ((eulerphi(m) % 4) == 2); \\ Michel Marcus, Oct 02 2017
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PARI
upto(n) = {my(l=List()); forprime(p=3, n, if(p%4==3, forstep(e=1, logint(n,p), 2, listput(l,p^e); if(2*p^e <= n, listput(l,2*p^e))))); listsort(l); l} \\ David A. Corneth, Oct 02 2017
Formula
As 22 = 2 * 11^1, which is of the form 2 * p^k with p = 11 = 2 * 4 + 3 == 3 mod 4 and k = 1 which is odd, 22 is a term. - David A. Corneth, Oct 02 2017
Comments