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A099653 a(n) is the number of n-subsets (n=1,2,...,10) of the 10 decimal digits from which prime numbers can be constructed including all n distinct digits either with or without repetitions; a(n) <= binomial(10,n). 4
5, 24, 96, 194, 246, 209, 120, 45, 10, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..83.

FORMULA

a(n) = binomial(10,n) - binomial(6,n) - binomial(4,n); number of n-digit subsets minus "antiprime-digit subclasses" selected from {0, 2, 4, 5, 6, 8} and {0, 3, 6, 9} digit collections.

EXAMPLE

n=1: {11,2,3,5,7} represent the 1-subsets; a(1) = 5;

n=2: A099651 includes least terms of each a(2) = 24 subsets;

n=5: a(5) = binomial(10,5) - binomial(6,5) - binomial(4,5) = 210 - 6 - 0 = 246;

n=6: each of the 6-subsets is good for primes except {0,2,4,5,6,8} so a(6) = 210 - 1.

n=7,8,9,10: a(n) = binomial(10,n).

Total number of relevant subset classes from the 1023 nonempty k-digit subsets equals 950. See also A099654.

MATHEMATICA

Table[5 Boole[n == 1] + Binomial[10, n] - Binomial[6, n] - Binomial[4, n], {n, 83}] (* Michael De Vlieger, Jul 24 2017 *)

CROSSREFS

Cf. A099651, A099654, A099756.

Sequence in context: A212349 A268370 A087095 * A270126 A276139 A078820

Adjacent sequences: A099650 A099651 A099652 * A099654 A099655 A099656

KEYWORD

base,nonn

AUTHOR

Labos Elemer, Nov 15 2004

STATUS

approved

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Last modified February 5 09:24 EST 2023. Contains 360084 sequences. (Running on oeis4.)