A069844 Number of distinct primes obtained by inserting a 3 at all possible places in n. This includes prefixing and suffixing.

2, 1, 0, 1, 1, 0, 2, 1, 0, 1, 3, 0, 1, 0, 0, 1, 3, 0, 2, 0, 0, 1, 1, 0, 0, 1, 0, 1, 2, 0, 2, 0, 0, 0, 1, 0, 2, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 2, 1, 0, 1, 1, 0, 0, 1, 0, 0, 2, 0, 2, 0, 0, 1, 1, 0, 2, 1, 0, 0, 0, 0, 2, 1, 0, 0, 1, 0, 2, 0, 0, 1, 1, 0, 1, 1, 0, 1, 2, 0, 0, 0, 0, 0, 1, 0, 2, 1, 0, 0, 3, 0, 2, 0, 0

Offset

1,1

Links

Table of n, a(n) for n=1..105.

Example

See the example in A069842.

Mathematica

Table[ Count[ PrimeQ[ Union[ FromDigits /@ Table[ Insert[ IntegerDigits[n], 3, j], {j, 1, Floor[ Log[10, n] + 2]}]]], True], {n, 1, 105}]

Crossrefs

Cf. A069842, A069843, A069845, A069846, A069847, A069848, A069849, A069850 and A069851.

Sequence in context: A081285 A255361 A341685 * A233006 A145152 A124327

Adjacent sequences: A069841 A069842 A069843 * A069845 A069846 A069847

Keyword

base,nonn

Author

Amarnath Murthy, Apr 16 2002

Extensions

Edited and extended by Robert G. Wilson v, Apr 18 2002

Status

approved