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A087097 Dismal primes (cf. A087062). +0
10
19, 29, 39, 49, 59, 69, 79, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 109, 209, 219, 309, 319, 329, 409, 419, 429, 439, 509, 519, 529, 539, 549, 609, 619, 629, 639, 649, 659, 709, 719, 729, 739, 749, 759, 769, 809, 819, 829, 839, 849, 859, 869, 879, 901, 902, 903, 904, 905, 906, 907, 908, 909, 912, 913, 914, 915, 916, 917, 918, 919, 923, 924, 925, 926, 927, 928, 929, 934, 935, 936, 937, 938, 939, 945, 946, 947, 948, 949, 956, 957, 958, 959, 967, 968, 969, 978, 979, 989 (list; graph; listen)
OFFSET

1,1

COMMENT

9 is the multiplicative unit. A number n is a dismal prime if it is not a dismal product (see A087062 for definition) r*s where neither r nor s is 9.

All dismal primes must contain a 9, so this is a subset of A011539.

Is this the same as A088474? - Ralf Stephan, Mar 06 2004

LINKS

D. Applegate, C program for dismal arithmetic and number theory

Index entries for sequences related to dismal arithmetic

EXAMPLE

8 is not prime since 8 = 8*8. 9 is not prime since it is the multiplicative unit. 10 is not prime since 10 = 10*8. Thus 19 is the smallest prime.

CROSSREFS

Cf. A087062, A087636, A087638, A087984.

Adjacent sequences: A087094 A087095 A087096 this_sequence A087098 A087099 A087100

Sequence in context: A047985 A061763 A088474 this_sequence A038364 A109276 A133765

KEYWORD

nonn,easy

AUTHOR

Marc LeBrun (mlb(AT)well.com), Oct 20 2003

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Last modified November 8 20:39 EST 2009. Contains 166234 sequences.


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