The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A116283 k times k+7 gives the concatenation of two numbers m and m-1. 5
 7, 30, 64, 42753, 57241, 75423, 425072, 574922, 979528, 4301393, 5698601, 7028666, 4925000747, 5074999247, 7748266574, 8511881484, 8814851184, 7059602159672, 7106167933828, 7439286611621, 7485852385777 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..21. PROG (Python) def ok(n): s = str(n*(n+7)); h = (len(s)+1)//2; return int(s[:h])-1 == int(s[h:]) print(list(filter(ok, range(2, 10**6)))) # Michael S. Branicky, Jul 30 2021 CROSSREFS Cf. A001704, A028563. Cf. A116152, A116269, A116282, A116284, A116291. Sequence in context: A018831 A063128 A063148 * A139274 A086640 A083474 Adjacent sequences: A116280 A116281 A116282 * A116284 A116285 A116286 KEYWORD nonn,base AUTHOR Giovanni Resta, Feb 06 2006 STATUS approved

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

Last modified May 22 11:13 EDT 2024. Contains 372745 sequences. (Running on oeis4.)