A104883 - OEIS

%I #48 Jun 14 2022 02:26:25

%S 4,5,8,7,24,11,54,51,22,117,222,19,114,87,46,207,216,61,258,291,128,

%T 591,336,43,306,423,136,519,492,97,888,951,146,537,318,163,1656,561,

%U 238,699,732,191,864,1365,286,1353,1674,229,1422,1671,802,2451,876,283,576,2577

%N a(n) is the smallest number k such that A082467(k) = n.

%C This is simply the smallest inverse to A082467. Note that A082467 has offset 4. - _N. J. A. Sloane_, Jan 15 2020

%H Amiram Eldar, <a href="/A104883/b104883.txt">Table of n, a(n) for n = 1..1000</a>

%t f[n_] := Block[{k}, If[ OddQ[n], k = 2, k = 1]; While[ !PrimeQ[n - k] || !PrimeQ[n + k], k += 2]; k]; t = Table[ f[n], {n, 4, 2600}]; u = Table[0, {60}]; Do[a = t[[n]]; If[a < 61 && u[[a]] == 0, u[[a]] = n + 3], {n, 2597}]; u

%o (PARI) a082467(n) = my(k=1); while(isprime(n-k)*isprime(n+k) == 0, k++); k;

%o a(n) = my(k=4); while (a082467(k) != n, k++); k; \\ _Michel Marcus_, Feb 12 2020

%Y Cf. A082467.

%Y Records are in A104884.

%K nonn

%O 1,1

%A _Benoit Cloitre_ and _Robert G. Wilson v_, Mar 28 2005

%E Definition corrected by _Giovanni Resta_. - _N. J. A. Sloane_, Jan 15 2020