The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A350233 Integers that are divisible by 5 and not by 4, and whose reverse is divisible by 4 and not by 5. 1
 25, 65, 210, 215, 230, 235, 250, 255, 270, 275, 290, 295, 405, 425, 445, 465, 485, 610, 615, 630, 635, 650, 655, 670, 675, 690, 695, 805, 825, 845, 865, 885, 2105, 2110, 2115, 2125, 2130, 2135, 2145, 2150, 2155, 2165, 2170, 2175, 2185, 2190, 2195, 2305, 2310, 2315, 2325, 2330, 2335 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers beginning with 21, 23, 25, 27, 29, 40, 42, 44, 46, 48, 61, 63, 65, 67, 69, 80, 82, 84, 86, 88 and ending with 05, 10, 15, 25, 30, 35, 45, 50, 55, 65, 70, 75, 85, 90, 95. The number of d-digit terms is 3*10^(d-2) for d >= 3. - Jianing Song, Dec 24 2021 LINKS Table of n, a(n) for n=1..53. Ana Rechtman, Décembre 2021, 3e défi, Images des Mathématiques, CNRS, 2021. EXAMPLE 25 is term since it is divisible by 5 and not by 4, while 52, it reverse, is divisible by 4 and not by 5. MATHEMATICA Select[5 * Range[500], ! Divisible[#, 4] && Divisible[(r = IntegerReverse[#]), 4] && ! Divisible[r, 5] &] (* Amiram Eldar, Dec 21 2021 *) PROG (PARI) isok(k) = if ((k%4) && !(k%5), k=fromdigits(Vecrev(digits(k))); (k%5) && !(k%4)); (Python) from itertools import count, islice def A350233gen(): return filter(lambda n:(m := int(str(n)[::-1])) % 5 and not m % 4, filter(lambda n: n % 4 and not n % 5, count(1))) A350233_list = list(islice(A350233gen(), 20)) # Chai Wah Wu, Dec 21 2021 CROSSREFS Cf. A004086, A350232. Subsequence of A008587. Sequence in context: A020283 A350207 A211462 * A278855 A137186 A109676 Adjacent sequences: A350230 A350231 A350232 * A350234 A350235 A350236 KEYWORD nonn,base AUTHOR Michel Marcus, Dec 21 2021 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 June 4 21:13 EDT 2023. Contains 363130 sequences. (Running on oeis4.)