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A340211
a(n) is the least m such that A340210(m) = 2*n.
3
2, 55, 3, 10, 179, 7, 35, 274, 4, 241, 15, 23, 128, 452, 12, 425, 339, 9, 38, 239, 32, 262, 708, 6, 98, 118, 33, 279, 437, 24, 122, 419, 13, 604, 110, 131, 924, 1161, 41, 83, 2210, 62, 310, 987, 63, 418, 621, 18, 1569, 202, 225, 833, 1947, 125, 1477, 2486, 25, 1057, 3469, 34, 1226, 1544, 64, 1236
OFFSET
1,1
COMMENTS
2*n*prime(a(n))+prime(a(n)+1) and 2*n*prime(a(n))+prime(a(n)+2) are prime.
LINKS
EXAMPLE
For n=4, A340210(10)=8 and this is the first appearance of 8 in A340210, so a(4)=10.
MAPLE
f:= proc(n) local p, q, r, k;
p:= ithprime(n);
q:= ithprime(n+1);
r:= ithprime(n+2);
for k from 2 by 2 do
if isprime(k*p+q) and isprime(k*p+r) then return k fi
od
end proc:
V:= Vector(100): count:= 0:
for n from 2 while count < 100 do v:= A[n]/2;
if v <= 100 and V[v] = 0 then V[v]:= n; count:= count+1 fi
od:
CROSSREFS
Sequence in context: A359183 A089180 A034013 * A356985 A280209 A157262
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Dec 31 2020
STATUS
approved