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A154544 Primes p such that the smallest digit of p + the number of smallest digits of p is an even composite number. 1
3, 5, 7, 37, 43, 53, 59, 73, 79, 83, 97, 223, 227, 229, 347, 349, 359, 367, 379, 389, 397, 439, 443, 449, 463, 563, 569, 577, 587, 593, 599, 643, 653, 659, 673, 683, 739, 743, 757, 773, 839, 853, 857, 859, 863, 883, 887, 937, 953, 983, 997, 1117, 1151, 1171 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

3 is the smallest digit of 37 and it appears once; 3+1 is an even composite so 37 appears in this sequence.

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 p := ithprime(n) ; sdg := A054054(p) ; a := sdg +frequdig(p, sdg) ; if not isprime(a) and type(a, 'even') then printf("%d, ", p ) ; end if; end do: # R. J. Mathar, May 05 2010

MATHEMATICA

nsdQ[n_]:=Module[{sd=Min[IntegerDigits[n]], t}, t=sd+DigitCount[n, 10, sd]; t>2&&EvenQ[t]]; Select[Prime[Range[200]], nsdQ] (* Harvey P. Dale, Oct 17 2013 *)

CROSSREFS

Sequence in context: A069969 A067232 A106115 * A155034 A126359 A182373

Adjacent sequences:  A154541 A154542 A154543 * A154545 A154546 A154547

KEYWORD

nonn,base,less

AUTHOR

Juri-Stepan Gerasimov, Jan 11 2009

EXTENSIONS

Corrected (83, 443, 463 inserted) by R. J. Mathar, May 05 2010

STATUS

approved

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Last modified April 24 10:35 EDT 2019. Contains 322422 sequences. (Running on oeis4.)