A371337 Numbers k>0 such that k = (sum of digits of k^2) + (product of nonzero digits of k^2).

127, 1467, 3052, 5860, 653230, 3483702, 43352128, 783820873, 8092385362, 622196951140, 1061882796441600145, 178949702436677222562

Offset: 1

Author

René-Louis Clerc, Mar 19 2024

Keywords

• nonn
• base
• more

Examples

			1467^2 = 2152089, (2+1+5+2+8+9) + (2*1*5*2*8*9) = 27 + 1440 = 1467.
		

Links

• René-Louis Clerc, Nombres S+P, maxSP, minSP et |P-S|, pp. 1-15, 2024.

Crossrefs

Cf. A038364, A061763.

Programs

PARI

SplusP(k,r) = my(d=select(x->(x>0),digits(k^r))); vecsum(d) + vecprod(d) == k;
        resuSplusP(p,r)=for(k=1,10^p,if(SplusP(k,r) ==1,print1(k,",")))

Extensions

a(9)-a(12) from Chai Wah Wu, Apr 20 2024