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A096983 a(n) is the smallest prime whose base-n digits add up to a composite number. 0
23, 233, 7, 73, 11, 4801, 11, 17, 13, 19, 17, 337, 17, 23, 19, 31, 23, 151, 23, 29, 29, 31, 29, 73, 29, 41, 31, 37, 37, 619, 37, 41, 37, 43, 41, 61, 41, 47, 43, 61, 47, 67, 47, 53, 53, 61, 53, 73, 53, 59, 59, 61, 59, 79, 59, 71, 61, 67, 67, 109, 67, 71, 67, 73, 71, 101, 71, 83 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

Inspired by a homework problem in Crandall and Pomerance, Prime Numbers.

LINKS

Table of n, a(n) for n=2..69.

EXAMPLE

23 = 10111 (base 2) and 1+1+1+1=4, 233 = 22122 (base 3) and 2+2+1+2+2=9, 337 = 1,12,12 (base 13) and 1+12+12=25.

MATHEMATICA

f[n_] := Block[{p = PrimePi[n] + 1}, While[ PrimeQ[Plus @@ IntegerDigits[Prime[p], n]], p++ ]; Prime[p]]; Table[ f[n], {n, 2, 70}] (* Robert G. Wilson v, Aug 21 2004 *)

CROSSREFS

Sequence in context: A022715 A060189 A028824 * A140572 A140844 A168438

Adjacent sequences:  A096980 A096981 A096982 * A096984 A096985 A096986

KEYWORD

nonn,base

AUTHOR

John L. Drost, Aug 19 2004

EXTENSIONS

More terms from Robert G. Wilson v, Aug 21 2004

STATUS

approved

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Last modified October 26 14:28 EDT 2021. Contains 348267 sequences. (Running on oeis4.)