login
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
OFFSET
2,1
COMMENTS
Inspired by a homework problem in Crandall and Pomerance, Prime Numbers.
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
KEYWORD
nonn,base
AUTHOR
John L. Drost, Aug 19 2004
EXTENSIONS
More terms from Robert G. Wilson v, Aug 21 2004
STATUS
approved