Search: id:A064385 Results 1-1 of 1 results found. %I A064385 %S A064385 7,47,247,1247,6247,31247,156247,781247,3906247,19531247, %T A064385 97656247,488281247,2441406247,12207031247,61035156247, %U A064385 305175781247,1525878906247,7629394531247,38146972656247 %N A064385 2*5^n-3. %C A064385 5-th polygonal numbers for polygons of 5^n sides divided by 5: p(5,5^x)/ 5, where p(n,k)=(n/2)*(n*k-k+4-2*n). %C A064385 This sequence exhibits periodic digit repetition; e.g. the last digit repeats as 7, the penultimate as 4 and the antepenultimate as 2, all with a period of 1; the fourth-to-last digit repeats the sequence 1, 6 with a period of 2; the fifth-to-last repeats the sequence 3, 5, 8, 0; the sixth-to-last repeats 1, 7, 9, 5, 6, 2, 4, 0. And so on, it seems, for the other digits as the numbers grow. %H A064385 Harry J. Smith, Table of n, a(n) for n=1,...,100 %p A064385 p := proc(n,k) (n/2)*(n*k-k+4-2*n) end: for x from 1 to 19 do p(5,5^x)/ 5 od; q := proc(x) 2*5^x-3 end: for x from 1 to 19 do q(x) od; %o A064385 (PARI) p(n,k) = (n/2)*(n*k-k+4-2*n) for(x=1,19,print(p(5,5^x)/5)) q(x) = 2*5^x-3 for(x=1,19,print(q(x))) %o A064385 (PARI) { for (n=1, 100, write("b064385.txt", n, " ", 2*5^n - 3) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 13 2009] %Y A064385 Sequence in context: A009202 A093112 A091516 this_sequence A009260 A126635 A085352 %Y A064385 Adjacent sequences: A064382 A064383 A064384 this_sequence A064386 A064387 A064388 %K A064385 nonn,easy %O A064385 1,1 %A A064385 Daniel Dockery (drd(AT)peritus.virtualave.net), Sep 16, 2001 Search completed in 0.001 seconds