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

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A169669 (first digit of n) * (last digit of n) in decimal representation. 4
 0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 0, 6, 12, 18, 24, 30, 36, 42, 48, 54, 0, 7, 14, 21, 28, 35, 42, 49, 56, 63, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS a(n) = A000030(n)*A010879(n); a(n) = A115300(n) for n<=100, A115300(101) = 0; a(n) = A111707(n) for n<=109, A111707(110) = 1; 0 <= a(n) <= 81, range = A174995; a(10*n + n mod 10) = a(n); a(A008592(n)) = 0; A000030(a(A017281(n))) = A000030(A017281(n)); a(n) = a(A004086(n))*A168184(n); LINKS R. Zumkeller, Table of n, a(n) for n = 0..10000 PROG (Haskell) a169669 n = a000030 n * mod n 10 -- Reinhard Zumkeller, Apr 29 2015 CROSSREFS Cf. A000030, A008592, A010879, A111707, A115300, A174995. Sequence in context: A292678 A072595 A334832 * A111707 A115300 A085942 Adjacent sequences:  A169666 A169667 A169668 * A169670 A169671 A169672 KEYWORD base,nonn,hear,look AUTHOR Reinhard Zumkeller, Apr 05 2010 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 December 2 18:09 EST 2021. Contains 349445 sequences. (Running on oeis4.)