1,1

Equivalently, this sequence is the union of numbers of the form 25^n*(5*n+2) and numbers of the form 25^n*(5*n+3).

Table of n, a(n) for n=1..66.

a(n) = 2.4 n + O(log n). - Charles R Greathouse IV, Dec 19 2013

(PARI) is(n)=n/=25^valuation(n, 25); n%5==2||n%5==3 \\ Charles R Greathouse IV and V. Raman, Dec 19 2013

Cf. A055046, A055047, A233999.

Sequence in context: A214324 A102664 A055053 * A047221 A331078 A032967

Adjacent sequences: A233995 A233996 A233997 * A233999 A234000 A234001

nonn,easy

V. Raman, Dec 18 2013

approved