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A154534 Odd nonprimes n with smallest digit of n + number of smallest digits of n = odd nonprime. 1
77, 105, 201, 203, 205, 207, 209, 301, 303, 305, 309, 403, 405, 407, 501, 505, 507, 603, 605, 609, 703, 705, 707, 779, 801, 803, 805, 807, 899, 901, 903, 905, 909, 989, 1011, 1015, 1017, 1023, 1025, 1027, 1029, 1035, 1037, 1041, 1043, 1045, 1047, 1053, 1055 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..1000

EXAMPLE

If n=77=odd nonprime, 7=7 and 7+2=9=odd nonprime, thus 77 is in the sequence.  If n=105=odd nonprime, 0<1<5 and 0+1=1=odd nonprime, thus 105 is in the sequence.

MAPLE

filter:= proc(n) local L, m, q;

  if isprime(n) then return false fi;

  L:= convert(n, base, 10);

  m:= min(L);

  q:= m + numboccur(L, m);

  q::odd and not isprime(q)

end proc:

select(filter, [seq(2*i+1, i=0..1000)]); # Robert Israel, Apr 15 2015

CROSSREFS

Cf. A141468.

Sequence in context: A247682 A127335 A193570 * A235867 A274967 A229826

Adjacent sequences:  A154531 A154532 A154533 * A154535 A154536 A154537

KEYWORD

nonn,base

AUTHOR

Juri-Stepan Gerasimov, Jan 11 2009

EXTENSIONS

Edited by Alois P. Heinz, Apr 15 2015

STATUS

approved

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Last modified October 23 23:51 EDT 2019. Contains 328379 sequences. (Running on oeis4.)