0,2

a(n) = 26^n - 26*(25^(n - 1))

a(3) = 1326 because 26^3 - 26*(25^2) = 1326

Sequence in context: A139670 A037138 A091429 this_sequence A114052 A042303 A042300

Adjacent sequences: A106707 A106708 A106709 this_sequence A106711 A106712 A106713

nonn

Luca Colucci (lcolucci(AT)caridata.it), May 14 2005