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 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS 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: A046810 A262988 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

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