

A154528


Composites k such that (smallest digit of k) + (multiplicity of smallest digit of k) is an even composite.


0



9, 22, 34, 35, 36, 38, 39, 44, 56, 57, 58, 63, 65, 66, 75, 78, 85, 87, 88, 93, 95, 111, 224, 225, 226, 228, 232, 242, 252, 262, 272, 282, 292, 322, 333, 344, 345, 346, 348, 354, 355, 356, 357, 358, 364, 365, 366, 368, 369, 374, 375, 376, 377, 378, 384, 385, 386
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..57.


EXAMPLE

9 (composite) is a term because 9 + 1 = 10 (even composite);
22 (composite) is a term because 2 + 2 = 4 (even composite);
34 (composite) is a term because 3 + 1 = 4 (even composite).


MAPLE

frequdig := proc(n, dig) local f, d ; f := 0 ; for d in convert(n, base, 10) do if d = dig then f :=f+1; end if; end do; f ; end proc:
A054054 := proc(n) min(op(convert(n, base, 10)) ) ; end proc:
for n from 1 to 500 do c := A002808(n) ; sdg := A054054(c) ; a := sdg +frequdig(c, sdg) ; if type(a, 'even') and not isprime(a) then printf("%d, ", c ) ; end if; end do: # R. J. Mathar, May 05 2010


CROSSREFS

Cf. A002808.
Sequence in context: A228009 A330477 A295008 * A130861 A049730 A131895
Adjacent sequences: A154525 A154526 A154527 * A154529 A154530 A154531


KEYWORD

nonn,base


AUTHOR

JuriStepan Gerasimov, Jan 11 2009


EXTENSIONS

Corrected (28 replaced with 38, 269 with 369) by R. J. Mathar, May 05 2010
Name and Example section edited by Jon E. Schoenfield, Feb 11 2019


STATUS

approved



