A104883 a(n) is the smallest number k such that A082467(k) = n.

4, 5, 8, 7, 24, 11, 54, 51, 22, 117, 222, 19, 114, 87, 46, 207, 216, 61, 258, 291, 128, 591, 336, 43, 306, 423, 136, 519, 492, 97, 888, 951, 146, 537, 318, 163, 1656, 561, 238, 699, 732, 191, 864, 1365, 286, 1353, 1674, 229, 1422, 1671, 802, 2451, 876, 283, 576, 2577

Offset: 1

Author

Benoit Cloitre and Robert G. Wilson v, Mar 28 2005

Keywords

• nonn

Comments

This is simply the smallest inverse to A082467. Note that A082467 has offset 4. - N. J. A. Sloane, Jan 15 2020

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A082467.

Records are in A104884.

Programs

Mathematica

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

PARI

a082467(n) = my(k=1); while(isprime(n-k)*isprime(n+k) == 0, k++); k;
a(n) = my(k=4); while (a082467(k) != n, k++); k; \\ Michel Marcus, Feb 12 2020

Extensions

Definition corrected by Giovanni Resta. - N. J. A. Sloane, Jan 15 2020