1,1

Cf. A007623 Integers written in factorial base.

a(n) = A007623(n)_10 if prime = (A007623 Integers written in factorial base) interpreted as if in base 10, iff prime.

a(1) = 11 = 1*(2!) + 1*(1!) = A007623(3)_10.

a(2) = 101 = 1*(3!) + 0*(2!) + 1*(1!) = A007623(7)_10.

a(3) = 211 = 2*(3!) + 1*(2!) + 1*(1!) = A007623(15)_10.

a(4) = 311 = 3*(3!) + 1*(2!) + 1*(1!) = A007623(21)_10.

a(5) = 1021 = 1*(4!) + 0*(3!) + 2*(2!) + 1*(1!) = A007623(29)_10.

a(6) = 1201 = 1*(4!) + 2*(3!) + 0*(2!) + 1*(1!) = A007623(37)_10.

a(7) = 1301 = 1*(4!) + 3*(3!) + 0*(2!) + 1*(1!) = A007623(43)_10.

a(8) = 1321 = 1*(4!) + 3*(3!) + 2*(2!) + 1*(1!) = A007623(47)_10.

Cf. A000040, A007623.

Sequence in context: A068188 A032592 A142317 this_sequence A156307 A057532 A001603

Adjacent sequences: A121399 A121400 A121401 this_sequence A121403 A121404 A121405

base,easy,nonn

Jonathan Vos Post (jvospost3(AT)gmail.com), Sep 06 2006