A177835 Primes p for which a smaller prime q exists with A000120(q) >= 2*A000120(p)-1.
17, 37, 41, 67, 73, 97, 131, 137, 139, 149, 163, 193, 197, 257, 263, 269, 277, 281, 293, 337, 353, 389, 401, 449, 521, 523, 547, 577, 593, 641, 643, 673, 769, 773, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069, 1091, 1093, 1097, 1109, 1123, 1129, 1153, 1163, 1171
Offset: 1
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
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Maple
read("transforms") ;A000120 := proc(n) wt(n) ; end proc: isA177835 := proc(p) if isprime(p) then q := 2 ; while q < p do if A000120(q) >= 2*A000120(p)-1 then return true; end if; q := nextprime(q) ; end do: return false; else false; end if; end proc: for i from 1 to 2000 do if isA177835(ithprime(i)) then printf("%d,",ithprime(i)) ; end if; end do: # R. J. Mathar, May 31 2010 -
Mathematica
With[{b = DigitCount[Prime[Range[200]], 2, 1]}, Rest@ Prime[Position[2*b - 1 - FoldList[Max, b], ?(# <= 0 &)] // Flatten]] (* _Amiram Eldar, Jul 25 2023 *)
Extensions
keyword:base and more terms added by R. J. Mathar, May 31 2010
Comments