A342027 a(n) is the least m such that A341284(m) = 2*n*prime(m+1) - prime(m).
2, 3, 6, 16, 24, 42, 23, 50, 47, 133, 138, 67, 161, 106, 30, 675, 455, 338, 697, 137, 488, 692, 189, 934, 1863, 1552, 518, 450, 2036, 1815, 2856, 3635, 6784, 8781, 2787, 2790, 99, 11396, 3903, 2539, 9722, 1851, 6399, 7388, 6592, 24371, 12408, 14059, 32846, 21934, 13490, 72170, 42106, 15469, 45948
Offset: 1
Keywords
Examples
For k=4, A341284(16) = 419 = 2*4*prime(17)-prime(16) and a(4) = 16.
Links
- Robert Israel, Table of n, a(n) for n = 1..175
Crossrefs
Cf. A341284.
Programs
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Maple
N:= 60: # for a(1) to a(N) V:= Vector(N): count:= 0: g:= proc(n) local k, pn, p1; pn:= ithprime(n); p1:= ithprime(n+1); for k from 2*p1-pn by 2*p1 to 2*N*p1-pn do if isprime(k) then return (k+pn)/(2*p1) fi od; N+1 end proc: for n from 2 while count < N do v:= g(n); if v <= N and V[v] = 0 then V[v]:= n; count:= count+1 fi od: convert(V,list);
Formula
A341284(a(n)) = 2*n*prime(a(n)+1)-prime(a(n)).
Comments