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 A255535 Numbers representable as both b^c + b + c and x^y + x - y, where b, c, x, y are integers greater than 1. 1
 14, 88, 65548, 33554459, 387420510, 1099511627800, 35184372088855, 3656158440063002 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(1) = 14 = 3^2 + 3 + 2 = 2^4 + 2 - 4. a(2) = 88 = 3^4 + 3 + 4 = 9^2 + 9 - 2. a(3) = 65548 = 4^8 + 4 + 8 = 16^4 + 16 - 4. a(4) = 33554459 = 2^25 + 2 + 25 = 32^5 + 32 - 5. a(5) = 387420510 = 3^18 + 3 + 18 = 27^6 + 27 - 6. a(6) = 1099511627800 = 4^20 + 4 + 20 = 32^8 + 32 - 8. a(7) = 35184372088855 = 8^15 + 8 + 15 = 32^9 + 32 - 9. a(8) = 3656158440063002 = 6^20 + 6 + 20 = 36^10 + 36 - 10. PROG (Python) TOP = 100000000 a = [0]*TOP for y in range(2, TOP/2):   if 2**y+2+y>=TOP: break for x in range(2, TOP/2):     k = x**y+x+y     if k>=TOP: break     a[k]=1 for y in range(2, TOP/2):   if 2**y+2-y>=TOP: break for x in range(2, TOP/2):     k = x**y+x-y     if k>=TOP: break     if k>=0: a[k]|=2 print [n for n in range(TOP) if a[n]==3] CROSSREFS Cf. A254034. Sequence in context: A116343 A259473 A202785 * A034544 A248060 A186257 Adjacent sequences:  A255532 A255533 A255534 * A255536 A255537 A255538 KEYWORD nonn,more AUTHOR Alex Ratushnyak, Feb 24 2015 EXTENSIONS a(5)-a(8) from Lars Blomberg, May 19 2015 STATUS approved

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Last modified January 28 09:52 EST 2020. Contains 331319 sequences. (Running on oeis4.)