The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A099654

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A099654

a(n) is the number of n-subsets [n=1,2,...,10] of the 10 decimal digits from which no prime numbers can be constructed. See also A099653.
(history; published version)

#14 by N. J. A. Sloane at Tue Mar 28 15:05:48 EDT 2017

STATUS

proposed

approved

#13 by Indranil Ghosh at Mon Mar 27 09:15:02 EDT 2017

STATUS

editing

proposed

#12 by Indranil Ghosh at Mon Mar 27 09:14:54 EDT 2017

PROG

(Python)

from sympy import binomial

(Python) def a(n): return binomial(6, n) + binomial(4, n) - 5*(n==1) # Indranil Ghosh, Mar 27 2017

STATUS

proposed

editing

#11 by Indranil Ghosh at Mon Mar 27 09:13:55 EDT 2017

STATUS

editing

proposed

#10 by Indranil Ghosh at Mon Mar 27 09:12:56 EDT 2017

PROG

(PARI) a(n) = binomial(6, n) + binomial(4, n) - 5*(n==1); \\ Indranil Ghosh, Mar 27 2017

(Python) def a(n): return binomial(6, n) + binomial(4, n) - 5*(n==1) # Indranil Ghosh, Mar 27 2017

STATUS

proposed

editing

Discussion

Mon Mar 27

09:13

Indranil Ghosh: My codes are directly translated from Michael's Mmca code.

#9 by Michael De Vlieger at Sun Mar 26 15:27:27 EDT 2017

STATUS

editing

proposed

#8 by Michael De Vlieger at Sun Mar 26 15:26:59 EDT 2017

COMMENTS

Number of "antiprime-digit-subclasses".

Subsets were selected from {0, 2, 4, 5, 6, 8} and {0, 3, 6, 9} digit collections.

FORMULA

a(n) = binomial(6,n) + binomial(4,n) for n>1 Number of "antiprime-digit-subclasses". Subsets were selected from {0, 2, 4, 5, 6, 8} and {0, 3, 6, 9} digit collections.

a(n) = binomial(6,n) + binomial(4,n) for n > 1.

MATHEMATICA

Table[Binomial[6, n] + Binomial[4, n] - 5 Boole[n == 1], {n, 100}] (* Michael De Vlieger, Mar 26 2017 *)

STATUS

approved

editing

Discussion

Sun Mar 26

15:27

Michael De Vlieger: Some material in Formula appears to belong in Comments.

#7 by Wesley Ivan Hurt at Mon Dec 14 00:04:07 EST 2015

STATUS

proposed

approved

#6 by Jon E. Schoenfield at Sun Dec 13 17:41:37 EST 2015

STATUS

editing

proposed

#5 by Jon E. Schoenfield at Sun Dec 13 17:41:34 EST 2015

NAME

a[(n] ) is the number of n-subsets [n=1,2,...,10] of the 10 decimal digits from which no prime numbers can be constructed. See also A099653.

FORMULA

a[(n]) =C[ binomial(6, n]) +C[ binomial(4, n] ) for n>1 Number of "antiprime-digit-subclasses". Subsets were selected from {0, 2, 4, 5, 6, 8} and {0, 3, 6, 9} digit collections.

EXAMPLE

Total number of prime irrelevant subset-classes from the 1023 non-empty nonempty k-digit-subsets equals 5 + 21 + 24 + 16 + 6 + 1 = 73 = 1023 - 950. See also A099653.

STATUS

approved

editing