A299112 Record values in A243145.

1, 2, 6, 12, 16, 30, 42, 54, 66, 78, 105, 120, 156, 330, 525, 546, 831, 1071, 1251, 1386, 1875, 1890, 2136, 2241, 2331, 2541, 2565, 2736, 2871, 3165, 3606, 3885, 4710, 5106, 5220, 5505, 6375, 6390, 6426, 6615, 6786, 8310, 8571, 9066, 10050, 10176, 10221, 10611, 11865, 11955, 12096

Offset

1,2

Links

Table of n, a(n) for n=1..51.

Maple

f:= proc(n) local k;
  for k from (n mod 2)+1 by 2 do
    if isprime(n+k) and isprime(n+k^2) then return k fi
  od
end proc:
f(1):= 1:
vmax:= 0: recvals:= NULL:
for n from 1 to 10^7 do
    v:= f(n);
  if v > vmax then
     vmax:= v; recvals:= recvals, v;
    fi
od:
recvals;

Mathematica

f[n_] := Module[{k}, For[k = Mod[n, 2]+1, True, k += 2, If[PrimeQ[n + k] && PrimeQ[n + k^2], Return [k]]]]; f[1] = 1;
vmax = 0;
Reap[For[n = 1, n <= 10^6, n++, v = f[n]; If[v > vmax, vmax = v; Print["n = ", n, "  v = ", v]; Sow[v]]]][[2, 1]] (* Jean-François Alcover, Oct 16 2020, after Maple *)

Crossrefs

Cf. A243145, A299073.

Sequence in context: A084790 A130237 A053457 * A154030 A055560 A237719

Adjacent sequences: A299109 A299110 A299111 * A299113 A299114 A299115

Keyword

nonn

Author

Robert Israel, Feb 02 2018

Extensions

a(34)-a(51) from Chai Wah Wu, Sep 10 2019

Status

approved