A290496 First differences of A001751.

1, 1, 1, 1, 1, 3, 1, 2, 1, 3, 2, 3, 1, 3, 3, 2, 3, 3, 1, 3, 2, 3, 1, 6, 5, 1, 2, 1, 5, 4, 2, 1, 5, 3, 1, 3, 3, 5, 3, 4, 2, 3, 1, 2, 4, 5, 4, 5, 4, 3, 3, 2, 3, 4, 3, 2, 6, 1, 5, 3, 1, 6, 5, 1, 2, 10, 2, 1, 3, 2, 3, 4, 5, 3, 4, 5, 3, 1, 2, 4, 6, 2, 10, 3, 3, 5, 1

Offset: 1

Author

Michel Marcus, Aug 04 2017

Keywords

• nonn

Crossrefs

Cf. A001751, A290488, A290489, A290541.

Programs

Mathematica

With[{nn = 56}, Differences@ Union@ Flatten@ {#, 2 TakeWhile[#, # < Prime[nn]/2 &]} &@ Prime@ Range@ nn]

PARI

lista(nn) = {last = 2; for (n=3, nn, if (isprime(n) || (!(n%2) && isprime(n/2)), print1(n - last, ", "); last = n;););}