

A069842


Number of distinct primes obtained by inserting a 1 at all possible places in n. This includes prefixing and suffixing.


9



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

1,3


LINKS

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


EXAMPLE

a(13) = 2 because 13 > 113, 113, 131 > 113 and 131 which are both prime.


MATHEMATICA

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


CROSSREFS

Cf. A069843, A069844, A069845, A069846, A069847, A069848, A069849, A069850, A069851.
Sequence in context: A178651 A046810 A039999 * A083056 A244422 A061896
Adjacent sequences: A069839 A069840 A069841 * A069843 A069844 A069845


KEYWORD

base,nonn


AUTHOR

Amarnath Murthy, Apr 16 2002


EXTENSIONS

More terms from Vladeta Jovovic, Apr 17 2002
Edited by Robert G. Wilson v, Apr 18 2002


STATUS

approved



