The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A339748 a(n) = (6^(valuation(n, 6) + 1) - 1) / 5. 2
 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 43, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 43, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 COMMENTS Sum of powers of 6 dividing n. LINKS FORMULA G.f.: Sum_{k>=0} 6^k * x^(6^k) / (1 - x^(6^k)). L.g.f.: -log(Product_{k>=0} (1 - x^(6^k))). Dirichlet g.f.: zeta(s) / (1 - 6^(1 - s)). MATHEMATICA Table[(6^(IntegerExponent[n, 6] + 1) - 1)/5, {n, 1, 100}] nmax = 100; CoefficientList[Series[Sum[6^k x^(6^k)/(1 - x^(6^k)), {k, 0, Floor[Log[6, nmax]] + 1}], {x, 0, nmax}], x] // Rest CROSSREFS Cf. A038712, A080278, A088842, A122841, A234959, A323921, A339747. Sequence in context: A010143 A101027 A129408 * A325470 A240831 A170824 Adjacent sequences:  A339745 A339746 A339747 * A339749 A339750 A339751 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Dec 15 2020 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 19 12:51 EDT 2021. Contains 345129 sequences. (Running on oeis4.)